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Products by Mozilla Sorted by Most Security Vulnerabilities since 2018

Mozilla Firefox2359 vulnerabilities
Open source web browser

Mozilla Thunderbird1577 vulnerabilities
Email client

Mozilla FireFox Extended Support Release (ESR)1125 vulnerabilities

Mozilla SeaMonkey286 vulnerabilities
Browser, email and newsgroup client

Mozilla Thunderbird Esr217 vulnerabilities

Mozilla Network Security Services28 vulnerabilities

Mozilla Focus24 vulnerabilities

Mozilla Firefox Mobile21 vulnerabilities

Mozilla Firefox Focus17 vulnerabilities

Mozilla9 vulnerabilities

Mozilla Nss8 vulnerabilities

Mozilla Firefox Os5 vulnerabilities

Mozilla Vpn4 vulnerabilities

Mozilla Nunjucks1 vulnerability

Mozilla Zamboni1 vulnerability

Mozilla Netscape Portable Runtime1 vulnerability

Recent Mozilla Security Advisories

Advisory	Title	Published
mfsa2026-77	Security Vulnerabilities fixed in Firefox ESR 153.1 mfsa2026-77	August 18, 2026
mfsa2026-79	Security Vulnerabilities fixed in Thunderbird 140.14 mfsa2026-79	August 18, 2026
mfsa2026-78	Security Vulnerabilities fixed in Thunderbird 154 mfsa2026-78	August 18, 2026
mfsa2026-75	Security Vulnerabilities fixed in Firefox ESR 115.39 mfsa2026-75	August 18, 2026
mfsa2026-76	Security Vulnerabilities fixed in Firefox ESR 140.14 mfsa2026-76	August 18, 2026
mfsa2026-80	Security Vulnerabilities fixed in Thunderbird 153.1 mfsa2026-80	August 18, 2026
mfsa2026-74	Security Vulnerabilities fixed in Firefox 154 mfsa2026-74	August 18, 2026
mfsa2026-73	Security Vulnerabilities fixed in Firefox for Android 153.0.3 mfsa2026-73	August 4, 2026
mfsa2026-68	Security Vulnerabilities fixed in Firefox 153 mfsa2026-68	July 21, 2026
mfsa2026-72	Security Vulnerabilities fixed in Thunderbird 140.13 mfsa2026-72	July 21, 2026

Known Exploited Mozilla Vulnerabilities

The following Mozilla vulnerabilities have been marked by CISA as Known to be Exploited by threat actors.

Title	Description	Added
Mozilla Multiple Products Remote Code Execution Vulnerability	Mozilla Firefox, SeaMonkey, and Thunderbird contain an unspecified vulnerability when JavaScript is enabled. This allows remote attackers to execute arbitrary code via vectors related to nsCSSFrameConstructor::ContentAppended, the appendChild method, incorrect index tracking, and the creation of multiple frames, which triggers memory corruption. CVE-2010-3765 Exploit Probability: 83.3%	October 6, 2025
Mozilla Firefox Use-After-Free Vulnerability	Mozilla Firefox and Firefox ESR contain a use-after-free vulnerability in Animation timelines that allows for code execution in the content process. CVE-2024-9680 Exploit Probability: 23.2%	October 15, 2024
Mozilla Firefox, Firefox ESR, and Thunderbird Use-After-Free Vulnerability	Mozilla Firefox, Firefox ESR, and Thunderbird contain a use-after-free vulnerability in SVG Animation, targeting Firefox and Tor browser users on Windows. CVE-2016-9079 Exploit Probability: 87.4%	June 22, 2023
Mozilla Firefox Security Feature Bypass Vulnerability	Moxilla Firefox allows remote attackers to bypass the Same Origin Policy to read arbitrary files or gain privileges. CVE-2015-4495 Exploit Probability: 68.7%	May 25, 2022
Mozilla Firefox and Thunderbird Type Confusion Vulnerability	Mozilla Firefox and Thunderbird contain a type confusion vulnerability that can occur when manipulating JavaScript objects due to issues in Array.pop, allowing for an exploitable crash. CVE-2019-11707 Exploit Probability: 37.7%	May 23, 2022
Mozilla Firefox and Thunderbird Sandbox Escape Vulnerability	Mozilla Firefox and Thunderbird contain a sandbox escape vulnerability that could result in remote code execution. CVE-2019-11708 Exploit Probability: 55.9%	May 23, 2022
Mozilla Firefox and Thunderbird Denial-of-Service Vulnerability	Mozilla Firefox and Thunderbird do not properly handle onreadystatechange events in conjunction with page reloading, which allows remote attackers to cause a denial-of-service or possibly execute arbitrary code via a crafted web site. CVE-2013-1690 Exploit Probability: 69.0%	March 28, 2022
Mozilla Firefox Use-After-Free Vulnerability	Mozilla Firefox contains a use-after-free vulnerability in WebGPU IPC Framework which can be exploited to perform arbitrary code execution. CVE-2022-26486 Exploit Probability: 2.3%	March 7, 2022
Mozilla Firefox Use-After-Free Vulnerability	Mozilla Firefox contains a use-after-free vulnerability in XSLT parameter processing which can be exploited to perform arbitrary code execution. CVE-2022-26485 Exploit Probability: 13.8%	March 7, 2022
Mozilla Firefox Information Disclosure Vulnerability	Mozilla Firefox does not properly initialize data structures for the nsDOMSVGZoomEvent::mPreviousScale and nsDOMSVGZoomEvent::mNewScale functions, which allows remote attackers to obtain sensitive information from process memory via a crafted web site. CVE-2013-1675 Exploit Probability: 6.7%	March 3, 2022
Mozilla Firefox 74 and Firefox ESR 68.6 nsDocShell vulnerability	A race condition can cause a use-after-free when running the nsDocShell destructor. This vulnerability affects Thunderbird < 68.7.0, Firefox < 74.0.1, and Firefox ESR < 68.6.1. CVE-2020-6819 Exploit Probability: 3.0%	November 3, 2021
Mozilla Firefox 74 and Firefox ESR 68.6 ReadableStream vulnerability	A race condition can cause a use-after-free when handling a ReadableStream. This vulnerability affects Thunderbird < 68.7.0, Firefox < 74.0.1, and Firefox ESR < 68.6.1. CVE-2020-6820 Exploit Probability: 6.3%	November 3, 2021
Mozilla Firefox IonMonkey JIT compiler Type Confusion Vulnerability	Incorrect alias information in IonMonkey JIT compiler for setting array elements could lead to a type confusion. This vulnerability affects Firefox ESR < 68.4.1, Thunderbird < 68.4.1, and Firefox < 72.0.1 CVE-2019-17026 Exploit Probability: 46.9%	November 3, 2021

Of the known exploited vulnerabilities above, 4 are in the top 1%, or the 99th percentile of the EPSS exploit probability rankings. 5 known exploited Mozilla vulnerabilities are in the top 5% (95th percentile or greater) of the EPSS exploit probability rankings.

By the Year

In 2026 there have been 399 vulnerabilities in Mozilla with an average score of 7.8 out of ten. Last year, in 2025 Mozilla had 209 security vulnerabilities published. That is, 190 more vulnerabilities have already been reported in 2026 as compared to last year. However, the average CVE base score of the vulnerabilities in 2026 is greater by 0.30.

Year	Vulnerabilities	Average Score
2026	399	7.76
2025	209	7.46
2024	204	7.10
2023	202	7.24
2022	188	7.42
2021	158	7.12
2020	184	7.25
2019	152	7.53
2018	345	7.65

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

Recent Mozilla Security Vulnerabilities

CVE	Date	Vulnerability	Products
CVE-2026-74989	Aug 18, 2026	Memory corruption bugs in Firefox 153 Internally found bugs present in Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154 and Thunderbird 154.	Firefox Thunderbird
CVE-2026-74988	Aug 18, 2026	Firefox ESR 153.0 Memory Corruption Vulnerability (fixed in 153.1) Internally found bugs present in Thunderbird ESR 153.0 and Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74986	Aug 18, 2026	CSS Parsing Component Site Isolation Flaw Fixed in Firefox 154 & ESR 153.1 Site isolation issue in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74985	Aug 18, 2026	Firefox 154 ESR 153.1 Fixed PrivEsc in Enterprise Policies Privilege escalation in the Enterprise Policies component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74984	Aug 18, 2026	Race Condition in JS Engine, Firefox <154, fixed v154 Race condition in the JavaScript Engine component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74982	Aug 18, 2026	DoS in Firefox Widget component before 154/ESR153.1 Denial-of-service in the Widget component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74980	Aug 18, 2026	Clickjacking issue in the Downloads component in Firefox for Android Clickjacking issue in the Downloads component in Firefox for Android. This vulnerability was fixed in Firefox 154.	Firefox
CVE-2026-74981	Aug 18, 2026	Site isolation issue in the Audio/Video: Web Codecs component Site isolation issue in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74979	Aug 18, 2026	Mitigation bypass in the Add-ons Manager component Mitigation bypass in the Add-ons Manager component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74978	Aug 18, 2026	Clickjacking issue in the Widget component Clickjacking issue in the Widget component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74975	Aug 18, 2026	Spoofing issue in the Downloads component in Firefox for Android Spoofing issue in the Downloads component in Firefox for Android. This vulnerability was fixed in Firefox 154.	Firefox
CVE-2026-74968	Aug 18, 2026	Site isolation issue in the Graphics: WebRender component Site isolation issue in the Graphics: WebRender component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74970	Aug 18, 2026	Site isolation issue in the Graphics component Site isolation issue in the Graphics component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74977	Aug 18, 2026	Integer overflow in the Graphics component Integer overflow in the Graphics component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74956	Aug 18, 2026	Same-origin policy bypass in the DOM: Service Workers component Same-origin policy bypass in the DOM: Service Workers component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74958	Aug 18, 2026	Information disclosure in the WebRTC component Information disclosure in the WebRTC component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74961	Aug 18, 2026	Side-channel in the Web Audio component Side-channel in the Web Audio component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74966	Aug 18, 2026	Information disclosure in the Form Autofill component Information disclosure in the Form Autofill component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74951	Aug 18, 2026	Clickjacking issue in Firefox for Android Clickjacking issue in Firefox for Android. This vulnerability was fixed in Firefox 154.	Firefox
CVE-2026-74952	Aug 18, 2026	Privilege escalation in the Application Update component Privilege escalation in the Application Update component. This vulnerability was fixed in Firefox 154 and Thunderbird 154.	Firefox Thunderbird
CVE-2026-74955	Aug 18, 2026	Privilege escalation in the Request Handling component Privilege escalation in the Request Handling component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74954	Aug 18, 2026	Information disclosure due to side-channel in the Storage: Cache API component Information disclosure due to side-channel in the Storage: Cache API component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74937	Aug 18, 2026	Use-after-free in the JavaScript: GC component Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74950	Aug 18, 2026	Privilege escalation in the Downloads API component Privilege escalation in the Downloads API component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74938	Aug 18, 2026	Mitigation bypass in the JavaScript: GC component Mitigation bypass in the JavaScript: GC component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74947	Aug 18, 2026	Privilege escalation due to invalid pointer in the Graphics component Privilege escalation due to invalid pointer in the Graphics component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74987	Aug 18, 2026	Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153 Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74990	Aug 18, 2026	Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153 Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-75874	Aug 18, 2026	Sandbox escape in the Remote Settings Client component Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154 and Thunderbird 154.	Firefox Thunderbird
CVE-2026-74983	Aug 18, 2026	Mitigation bypass in the Data Loss Prevention component Mitigation bypass in the Data Loss Prevention component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74976	Aug 18, 2026	JIT miscompilation in the JavaScript Engine: JIT component JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74974	Aug 18, 2026	Same-origin policy bypass in the Graphics: ImageLib component Same-origin policy bypass in the Graphics: ImageLib component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74973	Aug 18, 2026	Race condition, use-after-free in the Graphics component Race condition, use-after-free in the Graphics component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74972	Aug 18, 2026	Information disclosure in the DOM: Push Subscriptions component Information disclosure in the DOM: Push Subscriptions component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74971	Aug 18, 2026	Information disclosure in the DOM: UI Events & Focus Handling component Information disclosure in the DOM: UI Events & Focus Handling component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74969	Aug 18, 2026	Use-after-free in the Layout: Text and Fonts component Use-after-free in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74967	Aug 18, 2026	Same-origin policy bypass in the Audio/Video: Playback component Same-origin policy bypass in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74965	Aug 18, 2026	Privilege escalation in the Shell Integration component Privilege escalation in the Shell Integration component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74964	Aug 18, 2026	Integer overflow in the Graphics component Integer overflow in the Graphics component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74963	Aug 18, 2026	Same-origin policy bypass in the Networking: Cookies component Same-origin policy bypass in the Networking: Cookies component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74962	Aug 18, 2026	Site isolation issue in the Networking: Cookies component Site isolation issue in the Networking: Cookies component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74960	Aug 18, 2026	Site isolation issue in the WebExtensions component Site isolation issue in the WebExtensions component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74959	Aug 18, 2026	Mitigation bypass in the Storage: Cache API component Mitigation bypass in the Storage: Cache API component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74957	Aug 18, 2026	Mitigation bypass in the Safe Browsing component Mitigation bypass in the Safe Browsing component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74953	Aug 18, 2026	Privilege escalation in the Networking: Cookies component Privilege escalation in the Networking: Cookies component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74949	Aug 18, 2026	Privilege escalation due to use-after-free in the Graphics: Canvas2D component Privilege escalation due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74945	Aug 18, 2026	Information disclosure in the Graphics: Text component Information disclosure in the Graphics: Text component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74944	Aug 18, 2026	Use-after-free in the DOM: Core & HTML component Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74946	Aug 18, 2026	Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird
CVE-2026-74948	Aug 18, 2026	Information disclosure in the Graphics component Information disclosure in the Graphics component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.	Firefox Thunderbird