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Recent Mozilla Firefox Security Advisories

Advisory Title Published
mfsa2021-28 Security Vulnerabilities fixed in Firefox 90 mfsa2021-28 July 13, 2021
mfsa2021-29 Security Vulnerabilities fixed in Firefox ESR 78.12 mfsa2021-29 July 13, 2021
mfsa2021-27 Security Vulnerabilities fixed in Firefox 89.0.1 mfsa2021-27 June 16, 2021
mfsa2021-25 Security Vulnerabilities fixed in Firefox for iOS 34 mfsa2021-25 June 1, 2021
mfsa2021-23 Security Vulnerabilities fixed in Firefox 89 mfsa2021-23 June 1, 2021
mfsa2021-24 Security Vulnerabilities fixed in Firefox ESR 78.11 mfsa2021-24 June 1, 2021
mfsa2021-20 Security Vulnerabilities fixed in Firefox 88.0.1, Firefox for Android 88.1.3 mfsa2021-20 May 5, 2021
mfsa2021-18 Security Vulnerabilities fixed in Firefox ESR 78.10.1 mfsa2021-18 May 4, 2021
mfsa2021-15 Security Vulnerabilities fixed in Firefox ESR 78.10 mfsa2021-15 April 19, 2021
mfsa2021-16 Security Vulnerabilities fixed in Firefox 88 mfsa2021-16 April 19, 2021

@firefox Tweets

RT @mozilla: Facebook claims they shut down the researchers accounts due to privacy problems with the Ad Observer. In our view, those claim…
Wed Aug 04 19:09:08 +0000 2021

"Big tech companies have the power to force each other’s hands and shape our lives. If they continue seeing that d… https://t.co/JyfZO1Gslb
Thu Jul 29 19:00:30 +0000 2021

Be efficiently . . . efficient. Type a % sign in the address bar to search through all your open tabs, including… https://t.co/kaW6u3Zkqz
Tue Jul 27 17:15:08 +0000 2021

Ever had that panicked moment when you thought you lost your phone? You're not alone — but even when your phone i… https://t.co/a2Ei7l28p7
Wed Jul 21 23:35:00 +0000 2021

Companies want your contacts lists. This is why you should keep them private. https://t.co/CTLyC5Nop0
Fri Jul 16 19:45:02 +0000 2021

By the Year

In 2021 there have been 73 vulnerabilities in Mozilla Firefox with an average score of 6.9 out of ten. Last year Firefox had 132 security vulnerabilities published. Right now, Firefox is on track to have less security vulnerabilities in 2021 than it did last year. Last year, the average CVE base score was greater by 0.51

Year Vulnerabilities Average Score
2021 73 6.85
2020 132 7.36
2019 107 7.66
2018 102 7.77

It may take a day or so for new Firefox vulnerabilities to show up in the stats or in the list of recent security vulnerabilties. Additionally vulnerabilities may be tagged under a different product or component name.

Recent Mozilla Firefox Security Vulnerabilities

Mozilla developers reported memory safety bugs present in Firefox 88 and Firefox ESR 78.11

CVE-2021-29967 8.8 - High - June 24, 2021

Mozilla developers reported memory safety bugs present in Firefox 88 and Firefox ESR 78.11. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Thunderbird < 78.11, Firefox < 89, and Firefox ESR < 78.11.

Buffer Overflow

Mozilla developers reported memory safety bugs present in Firefox 88

CVE-2021-29966 8.8 - High - June 24, 2021

Mozilla developers reported memory safety bugs present in Firefox 88. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 89.

Buffer Overflow

Firefox for Android would become unstable and hard-to-recover when a website opened too many popups

CVE-2021-29962 4.3 - Medium - June 24, 2021

Firefox for Android would become unstable and hard-to-recover when a website opened too many popups. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 89.

Improper Resource Shutdown or Release

When a download was initiated, the client did not check whether it was in normal or private browsing mode

CVE-2021-29958 4.3 - Medium - June 24, 2021

When a download was initiated, the client did not check whether it was in normal or private browsing mode, which led to private mode cookies being shared in normal browsing mode. This vulnerability affects Firefox for iOS < 34.

Exposure of Resource to Wrong Sphere

When Web Render components were destructed, a race condition could have caused undefined behavior, and we presume

CVE-2021-29952 7.5 - High - June 24, 2021

When Web Render components were destructed, a race condition could have caused undefined behavior, and we presume that with enough effort may have been exploitable to run arbitrary code. This vulnerability affects Firefox < 88.0.1 and Firefox for Android < 88.1.3.

Race Condition

Mozilla developers and community members reported memory safety bugs present in Firefox 87

CVE-2021-29947 8.8 - High - June 24, 2021

Mozilla developers and community members reported memory safety bugs present in Firefox 87. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 88.

Buffer Overflow

Ports that were written as an integer overflow above the bounds of a 16-bit integer could have bypassed port blocking restrictions when used in the Alt-Svc header

CVE-2021-29946 8.8 - High - June 24, 2021

Ports that were written as an integer overflow above the bounds of a 16-bit integer could have bypassed port blocking restrictions when used in the Alt-Svc header. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

Integer Overflow or Wraparound

Firefox used to cache the last filename used for printing a file

CVE-2021-29960 4.3 - Medium - June 24, 2021

Firefox used to cache the last filename used for printing a file. When generating a filename for printing, Firefox usually suggests the web page title. The caching and suggestion techniques combined may have lead to the title of a website visited during private browsing mode being stored on disk. This vulnerability affects Firefox < 89.

Incorrect Resource Transfer Between Spheres

When a user has already

CVE-2021-29959 4.3 - Medium - June 24, 2021

When a user has already allowed a website to access microphone and camera, disabling camera sharing would not fully prevent the website from re-enabling it without an additional prompt. This was only possible if the website kept recording with the microphone until re-enabling the camera. This vulnerability affects Firefox < 89.

AuthZ

A transient execution vulnerability, named Floating Point Value Injection (FPVI)

CVE-2021-29955 5.3 - Medium - June 24, 2021

A transient execution vulnerability, named Floating Point Value Injection (FPVI) allowed an attacker to leak arbitrary memory addresses and may have also enabled JIT type confusion attacks. (A related vulnerability, Speculative Code Store Bypass (SCSB), did not affect Firefox.). This vulnerability affects Firefox ESR < 78.9 and Firefox < 87.

Injection

A malicious webpage could have forced a Firefox for Android user into executing attacker-controlled JavaScript in the context of another domain

CVE-2021-29953 6.1 - Medium - June 24, 2021

A malicious webpage could have forced a Firefox for Android user into executing attacker-controlled JavaScript in the context of another domain, resulting in a Universal Cross-Site Scripting vulnerability. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected. Further details are being temporarily withheld to allow users an opportunity to update.*. This vulnerability affects Firefox < 88.0.1 and Firefox for Android < 88.1.3.

XSS

The WebAssembly JIT could miscalculate the size of a return type, which could lead to a null read and result in a crash

CVE-2021-29945 6.5 - Medium - June 24, 2021

The WebAssembly JIT could miscalculate the size of a return type, which could lead to a null read and result in a crash. *Note: This issue only affected x86-32 platforms. Other platforms are unaffected.*. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

Incorrect Calculation

A malicious website

CVE-2021-29965 5.3 - Medium - June 24, 2021

A malicious website that causes an HTTP Authentication dialog to be spawned could trick the built-in password manager to suggest passwords for the currently active website instead of the website that triggered the dialog. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 89.

Externally Controlled Reference to a Resource in Another Sphere

When styling and rendering an oversized `<select>` element, Firefox did not apply correct clipping which

CVE-2021-29961 4.3 - Medium - June 24, 2021

When styling and rendering an oversized `<select>` element, Firefox did not apply correct clipping which allowed an attacker to paint over the user interface. This vulnerability affects Firefox < 89.

AuthZ

Address bar search suggestions in private browsing mode were re-using session data from normal mode

CVE-2021-29963 4.3 - Medium - June 24, 2021

Address bar search suggestions in private browsing mode were re-using session data from normal mode. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 89.

Insufficient Verification of Data Authenticity

A race condition with requestPointerLock() and setTimeout() could have resulted in a user interacting with one tab when they believed they were on a separate tab

CVE-2021-24000 3.1 - Low - June 24, 2021

A race condition with requestPointerLock() and setTimeout() could have resulted in a user interacting with one tab when they believed they were on a separate tab. In conjunction with certain elements (such as &lt;input type="file"&gt;) this could have led to an attack where a user was confused about the origin of the webpage and potentially disclosed information they did not intend to. This vulnerability affects Firefox < 88.

Lack of escaping allowed HTML injection when a webpage was viewed in Reader View

CVE-2021-29944 6.1 - Medium - June 24, 2021

Lack of escaping allowed HTML injection when a webpage was viewed in Reader View. While a Content Security Policy prevents direct code execution, HTML injection is still possible. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 88.

XSS

When a user clicked on an FTP URL containing encoded newline characters (%0A and %0D), the newlines would have been interpreted as such and

CVE-2021-24002 8.8 - High - June 24, 2021

When a user clicked on an FTP URL containing encoded newline characters (%0A and %0D), the newlines would have been interpreted as such and allowed arbitrary commands to be sent to the FTP server. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

Argument Injection

A compromised content process could have performed session history manipulations it should not have been able to due to testing infrastructure

CVE-2021-24001 4.3 - Medium - June 24, 2021

A compromised content process could have performed session history manipulations it should not have been able to due to testing infrastructure that was not restricted to testing-only configurations. This vulnerability affects Firefox < 88.

Exposure of Resource to Wrong Sphere

If a Blob URL was loaded through some unusual user interaction, it could have been loaded by the System Principal and granted additional privileges

CVE-2021-23999 8.8 - High - June 24, 2021

If a Blob URL was loaded through some unusual user interaction, it could have been loaded by the System Principal and granted additional privileges that should not be granted to web content. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

Improper Privilege Management

Through complicated navigations with new windows, an HTTP page could have inherited a secure lock icon from an HTTPS page

CVE-2021-23998 6.5 - Medium - June 24, 2021

Through complicated navigations with new windows, an HTTP page could have inherited a secure lock icon from an HTTPS page. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

Insufficient Verification of Data Authenticity

Due to unexpected data type conversions, a use-after-free could have occurred when interacting with the font cache

CVE-2021-23997 8.8 - High - June 24, 2021

Due to unexpected data type conversions, a use-after-free could have occurred when interacting with the font cache. We presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox < 88.

Incorrect Conversion between Numeric Types

By utilizing 3D CSS in conjunction with Javascript, content could have been rendered outside the webpage's viewport, resulting in a spoofing attack

CVE-2021-23996 6.5 - Medium - June 24, 2021

By utilizing 3D CSS in conjunction with Javascript, content could have been rendered outside the webpage's viewport, resulting in a spoofing attack that could have been used for phishing or other attacks on a user. This vulnerability affects Firefox < 88.

When Responsive Design Mode was enabled, it used references to objects that were previously freed

CVE-2021-23995 8.8 - High - June 24, 2021

When Responsive Design Mode was enabled, it used references to objects that were previously freed. We presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

Operation on a Resource after Expiration or Release

A WebGL framebuffer was not initialized early enough, resulting in memory corruption and an out of bound write

CVE-2021-23994 8.8 - High - June 24, 2021

A WebGL framebuffer was not initialized early enough, resulting in memory corruption and an out of bound write. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

Missing Initialization of Resource

Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 3.6.24 and 4.x through 7

CVE-2011-3656 6.1 - Medium - June 02, 2021

Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 3.6.24 and 4.x through 7 allows remote attackers to inject arbitrary web script or HTML via vectors involving HTTP 0.9 errors, non-default ports, and content-sniffing.

XSS

A flaw in Mozilla's embedded certificate code might

CVE-2007-5967 6.5 - Medium - May 17, 2021

A flaw in Mozilla's embedded certificate code might allow web sites to install root certificates on devices without user approval.

Improper Certificate Validation

A texture upload of a Pixel Buffer Object could have confused the WebGL code to skip binding the buffer used to unpack it

CVE-2021-23981 8.1 - High - March 31, 2021

A texture upload of a Pixel Buffer Object could have confused the WebGL code to skip binding the buffer used to unpack it, resulting in memory corruption and a potentially exploitable information leak or crash. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.

Buffer Overflow

Using techniques that built on the slipstream research, a malicious webpage could have s

CVE-2021-23982 6.5 - Medium - March 31, 2021

Using techniques that built on the slipstream research, a malicious webpage could have scanned both an internal network's hosts as well as services running on the user's local machine utilizing WebRTC connections. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.

Inadequate Encryption Strength

By causing a transition on a parent node by removing a CSS rule

CVE-2021-23983 6.5 - Medium - March 31, 2021

By causing a transition on a parent node by removing a CSS rule, an invalid property for a marker could have been applied, resulting in memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 87.

Buffer Overflow

A malicious extension could have opened a popup window lacking an address bar

CVE-2021-23984 6.5 - Medium - March 31, 2021

A malicious extension could have opened a popup window lacking an address bar. The title of the popup lacking an address bar should not be fully controllable, but in this situation was. This could have been used to spoof a website and attempt to trick the user into providing credentials. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.

Authentication Bypass by Spoofing

If an attacker is able to alter specific about:config values (for example malware running on the user's computer), the Devtools remote debugging feature could have been enabled in a way

CVE-2021-23985 6.5 - Medium - March 31, 2021

If an attacker is able to alter specific about:config values (for example malware running on the user's computer), the Devtools remote debugging feature could have been enabled in a way that was unnoticable to the user. This would have allowed a remote attacker (able to make a direct network connection to the victim) to monitor the user's browsing activity and (plaintext) network traffic. This was addressed by providing a visual cue when Devtools has an open network socket. This vulnerability affects Firefox < 87.

Exposure of Resource to Wrong Sphere

A malicious extension with the 'search' permission could have installed a new search engine whose favicon referenced a cross-origin URL

CVE-2021-23986 6.5 - Medium - March 31, 2021

A malicious extension with the 'search' permission could have installed a new search engine whose favicon referenced a cross-origin URL. The response to this cross-origin request could have been read by the extension, allowing a same-origin policy bypass by the extension, which should not have cross-origin permissions. This cross-origin request was made without cookies, so the sensitive information disclosed by the violation was limited to local-network resources or resources that perform IP-based authentication. This vulnerability affects Firefox < 87.

Origin Validation Error

Mozilla developers and community members reported memory safety bugs present in Firefox 86 and Firefox ESR 78.8

CVE-2021-23987 8.8 - High - March 31, 2021

Mozilla developers and community members reported memory safety bugs present in Firefox 86 and Firefox ESR 78.8. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.

Buffer Overflow

Mozilla developers reported memory safety bugs present in Firefox 86

CVE-2021-23988 8.8 - High - March 31, 2021

Mozilla developers reported memory safety bugs present in Firefox 86. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 87.

Buffer Overflow

Mozilla developers reported memory safety bugs present in Firefox 84 and Firefox ESR 78.6

CVE-2021-23964 8.8 - High - February 26, 2021

Mozilla developers reported memory safety bugs present in Firefox 84 and Firefox ESR 78.6. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.

Buffer Overflow

Mozilla developers reported memory safety bugs present in Firefox 84

CVE-2021-23965 8.8 - High - February 26, 2021

Mozilla developers reported memory safety bugs present in Firefox 84. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 85.

Buffer Overflow

Mozilla developers reported memory safety bugs present in Firefox 85 and Firefox ESR 78.7

CVE-2021-23978 8.8 - High - February 26, 2021

Mozilla developers reported memory safety bugs present in Firefox 85 and Firefox ESR 78.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.

Mozilla developers reported memory safety bugs present in Firefox 85

CVE-2021-23979 8.8 - High - February 26, 2021

Mozilla developers reported memory safety bugs present in Firefox 85. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 86.

Buffer Overflow

If a user clicked into a specifically crafted PDF

CVE-2021-23953 4.3 - Medium - February 26, 2021

If a user clicked into a specifically crafted PDF, the PDF reader could be confused into leaking cross-origin information, when said information is served as chunked data. This vulnerability affects Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.

Using the new logical assignment operators in a JavaScript switch statement could have caused a type confusion

CVE-2021-23954 8.8 - High - February 26, 2021

Using the new logical assignment operators in a JavaScript switch statement could have caused a type confusion, leading to a memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.

Object Type Confusion

The browser could have been confused into transferring a pointer lock state into another tab, which could have lead to clickjacking attacks

CVE-2021-23955 6.1 - Medium - February 26, 2021

The browser could have been confused into transferring a pointer lock state into another tab, which could have lead to clickjacking attacks. This vulnerability affects Firefox < 85.

Clickjacking

An ambiguous file picker design could have confused users who intended to select and upload a single file into uploading a whole directory

CVE-2021-23956 6.5 - Medium - February 26, 2021

An ambiguous file picker design could have confused users who intended to select and upload a single file into uploading a whole directory. This was addressed by adding a new prompt. This vulnerability affects Firefox < 85.

Navigations through the Android-specific `intent` URL scheme could have been misused to escape iframe sandbox

CVE-2021-23957 7.4 - High - February 26, 2021

Navigations through the Android-specific `intent` URL scheme could have been misused to escape iframe sandbox. Note: This issue only affected Firefox for Android. Other operating systems are unaffected. This vulnerability affects Firefox < 85.

The browser could have been confused into transferring a screen sharing state into another tab, which would leak unintended information

CVE-2021-23958 6.5 - Medium - February 26, 2021

The browser could have been confused into transferring a screen sharing state into another tab, which would leak unintended information. This vulnerability affects Firefox < 85.

Exposure of Resource to Wrong Sphere

An XSS bug in internal error pages could have led to various spoofing attacks, including other error pages and the address bar

CVE-2021-23959 6.1 - Medium - February 26, 2021

An XSS bug in internal error pages could have led to various spoofing attacks, including other error pages and the address bar. Note: This issue only affected Firefox for Android. Other operating systems are unaffected. This vulnerability affects Firefox < 85.

XSS

Performing garbage collection on re-declared JavaScript variables resulted in a user-after-poison, and a potentially exploitable crash

CVE-2021-23960 8.8 - High - February 26, 2021

Performing garbage collection on re-declared JavaScript variables resulted in a user-after-poison, and a potentially exploitable crash. This vulnerability affects Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.

Further techniques that built on the slipstream research combined with a malicious webpage could have exposed both an internal network's hosts as well as services running on the user's local machine

CVE-2021-23961 7.4 - High - February 26, 2021

Further techniques that built on the slipstream research combined with a malicious webpage could have exposed both an internal network's hosts as well as services running on the user's local machine. This vulnerability affects Firefox < 85.

Incorrect use of the '<RowCountChanged>' method could have led to a user-after-poison and a potentially exploitable crash

CVE-2021-23962 8.8 - High - February 26, 2021

Incorrect use of the '<RowCountChanged>' method could have led to a user-after-poison and a potentially exploitable crash. This vulnerability affects Firefox < 85.

When sharing geolocation during an active WebRTC share

CVE-2021-23963 4.3 - Medium - February 26, 2021

When sharing geolocation during an active WebRTC share, Firefox could have reset the webRTC sharing state in the user interface, leading to loss of control over the currently granted permission. This vulnerability affects Firefox < 85.

Improper Preservation of Permissions

Firefox for Android suffered from a time-of-check-time-of-use vulnerability

CVE-2021-23977 5.3 - Medium - February 26, 2021

Firefox for Android suffered from a time-of-check-time-of-use vulnerability that allowed a malicious application to read sensitive data from application directories. Note: This issue is only affected Firefox for Android. Other operating systems are unaffected. This vulnerability affects Firefox < 86.

TOCTTOU

If Content Security Policy blocked frame navigation

CVE-2021-23968 4.3 - Medium - February 26, 2021

If Content Security Policy blocked frame navigation, the full destination of a redirect served in the frame was reported in the violation report; as opposed to the original frame URI. This could be used to leak sensitive information contained in such URIs. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.

Generation of Error Message Containing Sensitive Information

As specified in the W3C Content Security Policy draft, when creating a violation report, "User agents need to ensure

CVE-2021-23969 4.3 - Medium - February 26, 2021

As specified in the W3C Content Security Policy draft, when creating a violation report, "User agents need to ensure that the source file is the URL requested by the page, pre-redirects. If thats not possible, user agents need to strip the URL down to an origin to avoid unintentional leakage." Under certain types of redirects, Firefox incorrectly set the source file to be the destination of the redirects. This was fixed to be the redirect destination's origin. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.

Context-specific code was included in a shared jump table; resulting in assertions being triggered in multithreaded wasm code

CVE-2021-23970 6.5 - Medium - February 26, 2021

Context-specific code was included in a shared jump table; resulting in assertions being triggered in multithreaded wasm code. This vulnerability affects Firefox < 86.

assertion failure

When processing a redirect with a conflicting Referrer-Policy, Firefox would have adopted the redirect's Referrer-Policy

CVE-2021-23971 6.5 - Medium - February 26, 2021

When processing a redirect with a conflicting Referrer-Policy, Firefox would have adopted the redirect's Referrer-Policy. This would have potentially resulted in more information than intended by the original origin being provided to the destination of the redirect. This vulnerability affects Firefox < 86.

One phishing tactic on the web is to provide a link with HTTP Auth

CVE-2021-23972 8.8 - High - February 26, 2021

One phishing tactic on the web is to provide a link with HTTP Auth. For example 'https://www.phishingtarget.com@evil.com'. To mitigate this type of attack, Firefox will display a warning dialog; however, this warning dialog would not have been displayed if evil.com used a redirect that was cached by the browser. This vulnerability affects Firefox < 86.

When trying to load a cross-origin resource in an audio/video context a decoding error may have resulted, and the content of

CVE-2021-23973 6.5 - Medium - February 26, 2021

When trying to load a cross-origin resource in an audio/video context a decoding error may have resulted, and the content of that error may have revealed information about the resource. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.

Generation of Error Message Containing Sensitive Information

The DOMParser API did not properly process '<noscript>' elements for escaping

CVE-2021-23974 6.1 - Medium - February 26, 2021

The DOMParser API did not properly process '<noscript>' elements for escaping. This could be used as an mXSS vector to bypass an HTML Sanitizer. This vulnerability affects Firefox < 86.

The developer page about:memory has a Measure function for exploring what object types the browser has allocated and their sizes

CVE-2021-23975 6.5 - Medium - February 26, 2021

The developer page about:memory has a Measure function for exploring what object types the browser has allocated and their sizes. When this function was invoked we incorrectly called the sizeof function, instead of using the API method that checks for invalid pointers. This vulnerability affects Firefox < 86.

AuthZ

When accepting a malicious intent from other installed apps, Firefox for Android accepted manifests from arbitrary file paths and

CVE-2021-23976 8.1 - High - February 26, 2021

When accepting a malicious intent from other installed apps, Firefox for Android accepted manifests from arbitrary file paths and allowed declaring webapp manifests for other origins. This could be used to gain fullscreen access for UI spoofing and could also lead to cross-origin attacks on targeted websites. Note: This issue is a different issue from CVE-2020-26954 and only affected Firefox for Android. Other operating systems are unaffected. This vulnerability affects Firefox < 86.

Clickjacking

Side-channel information leakage in graphics in Google Chrome prior to 87.0.4280.66

CVE-2020-16012 4.3 - Medium - January 08, 2021

Side-channel information leakage in graphics in Google Chrome prior to 87.0.4280.66 allowed a remote attacker to leak cross-origin data via a crafted HTML page.

Certain blit values provided by the user were not properly constrained leading to a heap buffer overflow on some video drivers

CVE-2020-26971 8.8 - High - January 07, 2021

Certain blit values provided by the user were not properly constrained leading to a heap buffer overflow on some video drivers. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

Memory Corruption

The lifecycle of IPC Actors allows managed actors to outlive their manager actors; and the former must ensure

CVE-2020-26972 9.8 - Critical - January 07, 2021

The lifecycle of IPC Actors allows managed actors to outlive their manager actors; and the former must ensure that they are not attempting to use a dead actor they have a reference to. Such a check was omitted in WebGL, resulting in a use-after-free and a potentially exploitable crash. This vulnerability affects Firefox < 84.

Dangling pointer

Certain input to the CSS Sanitizer confused it, resulting in incorrect components being removed

CVE-2020-26973 8.8 - High - January 07, 2021

Certain input to the CSS Sanitizer confused it, resulting in incorrect components being removed. This could have been used as a sanitizer bypass. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

When flex-basis was used on a table wrapper, a StyleGenericFlexBasis object could have been incorrectly cast to the wrong type

CVE-2020-26974 8.8 - High - January 07, 2021

When flex-basis was used on a table wrapper, a StyleGenericFlexBasis object could have been incorrectly cast to the wrong type. This resulted in a heap user-after-free, memory corruption, and a potentially exploitable crash. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

Memory Corruption

When a malicious application installed on the user's device broadcast an Intent to Firefox for Android

CVE-2020-26975 6.5 - Medium - January 07, 2021

When a malicious application installed on the user's device broadcast an Intent to Firefox for Android, arbitrary headers could have been specified, leading to attacks such as abusing ambient authority or session fixation. This was resolved by only allowing certain safe-listed headers. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 84.

When a HTTPS pages was embedded in a HTTP page

CVE-2020-26976 6.5 - Medium - January 07, 2021

When a HTTPS pages was embedded in a HTTP page, and there was a service worker registered for the former, the service worker could have intercepted the request for the secure page despite the iframe not being a secure context due to the (insecure) framing. This vulnerability affects Firefox < 84.

By attempting to connect a website using an unresponsive port

CVE-2020-26977 6.5 - Medium - January 07, 2021

By attempting to connect a website using an unresponsive port, an attacker could have controlled the content of a tab while the URL bar displayed the original domain. *Note: This issue only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 84.

Using techniques that built on the slipstream research

CVE-2020-26978 6.1 - Medium - January 07, 2021

Using techniques that built on the slipstream research, a malicious webpage could have exposed both an internal network's hosts as well as services running on the user's local machine. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

When a user typed a URL in the address bar or the search bar and quickly hit the enter key, a website could sometimes capture

CVE-2020-26979 6.1 - Medium - January 07, 2021

When a user typed a URL in the address bar or the search bar and quickly hit the enter key, a website could sometimes capture that event and then redirect the user before navigation occurred to the desired, entered address. To construct a convincing spoof the attacker would have had to guess what the user was typing, perhaps by suggesting it. This vulnerability affects Firefox < 84.

Open Redirect

When an extension with the proxy permission registered to receive <all_urls>

CVE-2020-35111 4.3 - Medium - January 07, 2021

When an extension with the proxy permission registered to receive <all_urls>, the proxy.onRequest callback was not triggered for view-source URLs. While web content cannot navigate to such URLs, a user opening View Source could have inadvertently leaked their IP address. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

Mozilla developers reported memory safety bugs present in Firefox 83 and Firefox ESR 78.5

CVE-2020-35113 8.8 - High - January 07, 2021

Mozilla developers reported memory safety bugs present in Firefox 83 and Firefox ESR 78.5. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

Memory Corruption

Mozilla developers reported memory safety bugs present in Firefox 83

CVE-2020-35114 8.8 - High - January 07, 2021

Mozilla developers reported memory safety bugs present in Firefox 83. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 84.

Memory Corruption

In certain circumstances, the MCallGetProperty opcode

CVE-2020-26950 8.8 - High - December 09, 2020

In certain circumstances, the MCallGetProperty opcode can be emitted with unmet assumptions resulting in an exploitable use-after-free condition. This vulnerability affects Firefox < 82.0.3, Firefox ESR < 78.4.1, and Thunderbird < 78.4.2.

Dangling pointer

A parsing and event loading mismatch in Firefox's SVG code could have allowed load events to fire, even after sanitization

CVE-2020-26951 6.1 - Medium - December 09, 2020

A parsing and event loading mismatch in Firefox's SVG code could have allowed load events to fire, even after sanitization. An attacker already capable of exploiting an XSS vulnerability in privileged internal pages could have used this attack to bypass our built-in sanitizer. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

XSS

Incorrect bookkeeping of functions inlined during JIT compilation could have led to memory corruption and a potentially exploitable crash when handling out-of-memory errors

CVE-2020-26952 8.8 - High - December 09, 2020

Incorrect bookkeeping of functions inlined during JIT compilation could have led to memory corruption and a potentially exploitable crash when handling out-of-memory errors. This vulnerability affects Firefox < 83.

Memory Corruption

It was possible to cause the browser to enter fullscreen mode without displaying the security UI; thus making it possible to attempt a phishing attack or otherwise confuse the user

CVE-2020-26953 4.3 - Medium - December 09, 2020

It was possible to cause the browser to enter fullscreen mode without displaying the security UI; thus making it possible to attempt a phishing attack or otherwise confuse the user. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

Clickjacking

When accepting a malicious intent from other installed apps, Firefox for Android accepted manifests from arbitrary file paths and

CVE-2020-26954 4.3 - Medium - December 09, 2020

When accepting a malicious intent from other installed apps, Firefox for Android accepted manifests from arbitrary file paths and allowed declaring webapp manifests for other origins. This could be used to gain fullscreen access for UI spoofing and could also lead to cross-origin attacks on targeted websites. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 83.

When a user downloaded a file in Firefox for Android, if a cookie is set, it

CVE-2020-26955 6.5 - Medium - December 09, 2020

When a user downloaded a file in Firefox for Android, if a cookie is set, it would have been re-sent during a subsequent file download operation on the same domain, regardless of whether the original and subsequent request were in private and non-private browsing modes. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 83.

Reliance on Cookies without Validation and Integrity Checking

In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS

CVE-2020-26956 6.1 - Medium - December 09, 2020

In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

XSS

OneCRL was non-functional in the new Firefox for Android due to a missing service initialization

CVE-2020-26957 6.5 - Medium - December 09, 2020

OneCRL was non-functional in the new Firefox for Android due to a missing service initialization. This could result in a failure to enforce some certificate revocations. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 83.

Improper Initialization

Firefox did not block execution of scripts with incorrect MIME types when the response was intercepted and cached through a ServiceWorker

CVE-2020-26958 6.1 - Medium - December 09, 2020

Firefox did not block execution of scripts with incorrect MIME types when the response was intercepted and cached through a ServiceWorker. This could lead to a cross-site script inclusion vulnerability, or a Content Security Policy bypass. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

XSS

During browser shutdown

CVE-2020-26959 8.8 - High - December 09, 2020

During browser shutdown, reference decrementing could have occured on a previously freed object, resulting in a use-after-free, memory corruption, and a potentially exploitable crash. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

Dangling pointer

If the Compact() method was called on an nsTArray

CVE-2020-26960 8.8 - High - December 09, 2020

If the Compact() method was called on an nsTArray, the array could have been reallocated without updating other pointers, leading to a potential use-after-free and exploitable crash. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

Dangling pointer

When DNS over HTTPS is in use, it intentionally filters RFC1918 and related IP ranges

CVE-2020-26961 6.5 - Medium - December 09, 2020

When DNS over HTTPS is in use, it intentionally filters RFC1918 and related IP ranges from the responses as these do not make sense coming from a DoH resolver. However when an IPv4 address was mapped through IPv6, these addresses were erroneously let through, leading to a potential DNS Rebinding attack. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

Cross-origin iframes that contained a login form could have been recognized by the login autofill service, and populated

CVE-2020-26962 6.1 - Medium - December 09, 2020

Cross-origin iframes that contained a login form could have been recognized by the login autofill service, and populated. This could have been used in clickjacking attacks, as well as be read across partitions in dynamic first party isolation. This vulnerability affects Firefox < 83.

Clickjacking

Repeated calls to the history and location interfaces could have been used to hang the browser

CVE-2020-26963 4.3 - Medium - December 09, 2020

Repeated calls to the history and location interfaces could have been used to hang the browser. This was addressed by introducing rate-limiting to these API calls. This vulnerability affects Firefox < 83.

Some websites have a feature "Show Password" where clicking a button will change a password field into a textbook field

CVE-2020-26965 6.5 - Medium - December 09, 2020

Some websites have a feature "Show Password" where clicking a button will change a password field into a textbook field, revealing the typed password. If, when using a software keyboard that remembers user input, a user typed their password and used that feature, the type of the password field was changed, resulting in a keyboard layout change and the possibility for the software keyboard to remember the typed password. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

Improper Removal of Sensitive Information Before Storage or Transfer

When listening for page changes with a Mutation Observer, a malicious web page could confuse Firefox Screenshots into interacting with elements other than those

CVE-2020-26967 6.5 - Medium - December 09, 2020

When listening for page changes with a Mutation Observer, a malicious web page could confuse Firefox Screenshots into interacting with elements other than those that it injected into the page. This would lead to internal errors and unexpected behavior in the Screenshots code. This vulnerability affects Firefox < 83.

Mozilla developers reported memory safety bugs present in Firefox 82 and Firefox ESR 78.4

CVE-2020-26968 8.8 - High - December 09, 2020

Mozilla developers reported memory safety bugs present in Firefox 82 and Firefox ESR 78.4. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

Memory Corruption

Mozilla developers reported memory safety bugs present in Firefox 82

CVE-2020-26969 8.8 - High - December 09, 2020

Mozilla developers reported memory safety bugs present in Firefox 82. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 83.

Memory Corruption

When performing EC scalar point multiplication, the wNAF point multiplication algorithm was used;

CVE-2020-6829 5.3 - Medium - October 28, 2020

When performing EC scalar point multiplication, the wNAF point multiplication algorithm was used; which leaked partial information about the nonce used during signature generation. Given an electro-magnetic trace of a few signature generations, the private key could have been computed. This vulnerability affects Firefox < 80 and Firefox for Android < 80.

If a valid external protocol handler was referenced in an image tag, the resulting broken image size could be distinguished

CVE-2020-15680 5.3 - Medium - October 22, 2020

If a valid external protocol handler was referenced in an image tag, the resulting broken image size could be distinguished from a broken image size of a non-existent protocol handler. This allowed an attacker to successfully probe whether an external protocol handler was registered. This vulnerability affects Firefox < 82.

When multiple WASM threads had a reference to a module

CVE-2020-15681 7.5 - High - October 22, 2020

When multiple WASM threads had a reference to a module, and were looking up exported functions, one WASM thread could have overwritten another's entry in a shared stub table, resulting in a potentially exploitable crash. This vulnerability affects Firefox < 82.

When a link to an external protocol was clicked, a prompt was presented that allowed the user to choose what application to open it in

CVE-2020-15682 6.5 - Medium - October 22, 2020

When a link to an external protocol was clicked, a prompt was presented that allowed the user to choose what application to open it in. An attacker could induce that prompt to be associated with an origin they didn't control, resulting in a spoofing attack. This was fixed by changing external protocol prompts to be tab-modal while also ensuring they could not be incorrectly associated with a different origin. This vulnerability affects Firefox < 82.

Origin Validation Error

Mozilla developers and community members reported memory safety bugs present in Firefox 81 and Firefox ESR 78.3

CVE-2020-15683 9.8 - Critical - October 22, 2020

Mozilla developers and community members reported memory safety bugs present in Firefox 81 and Firefox ESR 78.3. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 78.4, Firefox < 82, and Thunderbird < 78.4.

Mozilla developers reported memory safety bugs present in Firefox 81

CVE-2020-15684 9.8 - Critical - October 22, 2020

Mozilla developers reported memory safety bugs present in Firefox 81. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 82.

When converting coordinates

CVE-2020-12400 4.7 - Medium - October 08, 2020

When converting coordinates from projective to affine, the modular inversion was not performed in constant time, resulting in a possible timing-based side channel attack. This vulnerability affects Firefox < 80 and Firefox for Android < 80.

Information Disclosure

During ECDSA signature generation

CVE-2020-12401 4.7 - Medium - October 08, 2020

During ECDSA signature generation, padding applied in the nonce designed to ensure constant-time scalar multiplication was removed, resulting in variable-time execution dependent on secret data. This vulnerability affects Firefox < 80 and Firefox for Android < 80.

Use of a Broken or Risky Cryptographic Algorithm

If Firefox is installed to a user-writable directory, the Mozilla Maintenance Service would execute updater.exe

CVE-2020-15663 8.8 - High - October 01, 2020

If Firefox is installed to a user-writable directory, the Mozilla Maintenance Service would execute updater.exe from the install location with system privileges. Although the Mozilla Maintenance Service does ensure that updater.exe is signed by Mozilla, the version could have been rolled back to a previous version which would have allowed exploitation of an older bug and arbitrary code execution with System Privileges. *Note: This issue only affected Windows operating systems. Other operating systems are unaffected.*. This vulnerability affects Firefox < 80, Thunderbird < 78.2, Thunderbird < 68.12, Firefox ESR < 68.12, and Firefox ESR < 78.2.

Improper Privilege Management

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