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Products by Mozilla Sorted by Most Security Vulnerabilities since 2018

Mozilla Firefox2791 vulnerabilities
Open source web browser

Mozilla Thunderbird2012 vulnerabilities
Email client

Mozilla FireFox Extended Support Release (ESR)1127 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
mfsa2026-123	Security Vulnerabilities fixed in Firefox 159.0.1 mfsa2026-123	November 3, 2026
mfsa2026-119	Security Vulnerabilities fixed in Firefox ESR 115.44 mfsa2026-119	October 27, 2026
mfsa2026-120	Security Vulnerabilities fixed in Firefox ESR 153.6 mfsa2026-120	October 27, 2026
mfsa2026-122	Security Vulnerabilities fixed in Thunderbird 153.6 mfsa2026-122	October 27, 2026
mfsa2026-121	Security Vulnerabilities fixed in Thunderbird 159 mfsa2026-121	October 27, 2026
mfsa2026-118	Security Vulnerabilities fixed in Firefox 159 mfsa2026-118	October 27, 2026
mfsa2026-117	Security Vulnerabilities fixed in Firefox for iOS 156.1 mfsa2026-117	October 26, 2026
mfsa2026-116	Security Vulnerabilities fixed in Firefox for Android 158.0.2 mfsa2026-116	October 21, 2026
mfsa2026-114	Security Vulnerabilities fixed in Thunderbird 158.0.1 mfsa2026-114	October 20, 2026
mfsa2026-115	Security Vulnerabilities fixed in Thunderbird 153.5.1 mfsa2026-115	October 20, 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: 83.2%	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: 68.6%	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: 38.0%	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: 2.4%	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: 14.3%	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: 7.1%	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: 46.3%	November 3, 2021

Of the known exploited vulnerabilities above, 5 are in the top 1%, or the 99th percentile of the EPSS exploit probability rankings. 4 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 845 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, 636 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 0.38.

Year	Vulnerabilities	Average Score
2026	845	7.84
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	7.52
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-2026-120572	Nov 03, 2026	Firefox 159: Incorrect Boundary Conditions in Layout (Block & Inline) Incorrect boundary conditions in the Layout: Block and Inline component. This vulnerability was fixed in Firefox 159.0.1.	Firefox
CVE-2026-118180	Oct 27, 2026	Thunderbird <159/153.6 Matrix homeserver URL leads to NTLM leak (Win) When logging in to a Matrix account, Thunderbird used the homeserver address provided in the server's login response without validating it. A malicious or compromised homeserver could provide a file: URL, causing Thunderbird to send all further Matrix requests of that session to local files or, on Windows, to an attacker-controlled network share, which could leak the user's NTLM credentials. The NTLM credential leak only affects Thunderbird on Windows. Other operating systems are unaffected. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.	Thunderbird
CVE-2026-118179	Oct 27, 2026	Thunderbird <=159/153.6 snews: SSRF & command injection (CVE-2026-118179) Clicking a news: or snews: link that referenced a message-ID made Thunderbird connect, without asking, to the host and port given in the link, even if it was not a configured news server. Line breaks in the message-ID were sent to the server unmodified, so a crafted link could send arbitrary commands to services reachable from the user's network. In addition, snews: links to such servers connected without TLS. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.	Thunderbird
CVE-2026-118178	Oct 27, 2026	Thunderbird <159, 153.6> Remote RSS Feed file URL Local File Read (NTLM Leak) A remote RSS feed could use the itunes:new-feed-url or newLocation element to permanently change its stored subscription URL to a file: URL. Thunderbird then read that location on every feed update. This allowed a malicious feed, or an attacker able to modify a feed delivered over HTTP, to make Thunderbird read local files and, on Windows, connect to an attacker-controlled network share, which could leak the user's NTLM credentials. The NTLM credential leak only affects Thunderbird on Windows. Other operating systems are affected by the local file read only. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.	Thunderbird
CVE-2026-118177	Oct 27, 2026	Thunderbird <159 pre) Calendar URL SSRF leads to NTLM credential leak When looking for calendars in a directory on a server, during account setup or when adding a new network calendar, Thunderbird accepted calendar locations pointing to other servers, local files or network shares. A malicious server, or a network attacker when the lookup used plain HTTP, could make Thunderbird subscribe to such a location. On Windows this could leak the user's NTLM credentials to an attacker-controlled host on every calendar refresh, and changes to the calendar could be written to the attacker's share or overwrite a local file. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.	Thunderbird
CVE-2026-118176	Oct 27, 2026	Thunderbird <159 Windows extended UNC bypass (NTLM leak) Thunderbird's check that prevents mailbox: URLs from accessing files on remote Windows network shares could be bypassed using extended-length UNC paths. Displaying a specially crafted email could cause Thunderbird to connect to an SMB server chosen by the attacker, disclosing the user's Windows account name and NTLM authentication data, which could be used for offline password cracking or relay attacks. This bug only affects Thunderbird on Windows. Other operating systems are unaffected. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.	Thunderbird
CVE-2026-118175	Oct 27, 2026	Thunderbird <159/153.6 Email Composition Content Disclosure When replying to, forwarding, or editing a crafted email message as new, Thunderbird could embed parts of a different message stored in the same folder into the message being composed, without showing a blocked content warning. If the user sent the message, the content of the other message was disclosed to the recipients. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.	Thunderbird
CVE-2026-118174	Oct 27, 2026	Thunderbird < 159 (Windows) OpenPGP attachment remote load NTLM leak When a message containing an OpenPGP key attachment was displayed, Thunderbird automatically loaded the attachment's content to offer importing the key. A sender could mark the attachment as an external attachment pointing to an arbitrary URL, which Thunderbird then loaded without any user interaction, bypassing remote content blocking. On Windows, a URL pointing to an attacker-controlled network share could leak the user's NTLM credentials. The NTLM credential leak only affects Thunderbird on Windows. On other operating systems, the issue allowed a remote request that bypassed remote content blocking. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.	Thunderbird
CVE-2026-118026	Oct 27, 2026	Mozilla Firefox/Thunderbird JS GC Invalid Pointer Invalid pointer in the JavaScript: GC component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118025	Oct 27, 2026	SVG component flaw in Firefox/Thunderbird (CVE-2026-118025) Other issue in the SVG component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118027	Oct 27, 2026	Firefox before 115.44 Frame Poisoning in Layout Component Frame poisoning in the Layout component. This vulnerability was fixed in Firefox ESR 115.44.	Firefox
CVE-2026-118024	Oct 27, 2026	Mozilla Firefox/Thunderbird Use-After-Free in Graphics Text Component Use-after-free in the Graphics: Text component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118023	Oct 27, 2026	Firefox/Thunderbird WebRender UAF Sandbox Escape (CVE-2026-118023) Sandbox escape due to use-after-free in the Graphics: WebRender component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118022	Oct 27, 2026	Firefox/Thunderbird Use-After-Free Sandbox Escape via Disability Access APIs Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118021	Oct 27, 2026	Mozilla Firefox/Thunderbird XPCOM UAF Sandbox Escape Sandbox escape due to use-after-free in the XPCOM component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118020	Oct 27, 2026	Use-After-Free in Firefox/Thunderbird Layout Component Use-after-free in the Layout component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118019	Oct 27, 2026	Mozilla Firefox/Thunderbird DOM File UAF Race Condition Race condition, use-after-free in the DOM: File component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118018	Oct 27, 2026	Firefox for Android Downloads component spoofing vulnerability (CVE-2026-118018) Spoofing issue in the Downloads component in Firefox for Android. This vulnerability was fixed in Firefox 159.	Firefox
CVE-2026-118017	Oct 27, 2026	Mozilla Firefox/Thunderbird SVG Use-After-Free Use-after-free in the SVG component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118016	Oct 27, 2026	Use-After-Free in Firefox DOM Core/HTML Component (CVE-2026-118016) Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118015	Oct 27, 2026	Firefox/Thunderbird Use-After-Free in DOM Core/HTML (CVE2026118015) Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118014	Oct 27, 2026	Mozilla Firefox/Thunderbird JIT Use-After-Free (CVE-2026-118014) Use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118013	Oct 27, 2026	Firefox/Thunderbird Use-After-Free in Layout Images/Video/HTML Frames Use-after-free in the Layout: Images, Video, and HTML Frames component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118012	Oct 27, 2026	Mozilla Firefox/Thunderbird DOM Animation UAF Use-after-free in the DOM: Animation component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118011	Oct 27, 2026	Firefox/Thunderbird CSS Parsing Frame Poisoning (CVE-2026-118011) Frame poisoning in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118010	Oct 27, 2026	Mozilla Firefox/Thunderbird Use-After-Free in Disability Access APIs Use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118009	Oct 27, 2026	Mozilla Firefox/Thunderbird Text Graphics UAF & Integer Overflow Integer overflow, use-after-free in the Graphics: Text component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118007	Oct 27, 2026	Mozilla Firefox/Thunderbird Use-After-Free in JS GC Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118006	Oct 27, 2026	Mozilla Firefox/Thunderbird WebRTC Signaling UAF PrivEsc Privilege escalation due to use-after-free in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118005	Oct 27, 2026	Use-After-Free in Mozilla WebRTC Signaling (Firefox/Thunderbird) Use-after-free in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.	Firefox Thunderbird
CVE-2026-118004	Oct 27, 2026	Mozilla Firefox/Thunderbird CSS Transitions Boundary Error pre159 Incorrect boundary conditions in the CSS Transitions and Animations component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-118003	Oct 27, 2026	Firefox/Thunderbird DNS info disclosure (<=158) Information disclosure in the Networking: DNS component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-118002	Oct 27, 2026	Mozilla Firefox/Thunderbird Networking Race Cond Info Disclosure (<=159) Information disclosure due to race condition in the Networking component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117999	Oct 27, 2026	Mozilla Firefox/Thunderbird IPC Race Condition (fixed in 159, ESR 153.6) Race condition in the IPC component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-118000	Oct 27, 2026	Firefox & Thunderbird HTTP Networking info disclosure before 159 Information disclosure in the Networking: HTTP component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117998	Oct 27, 2026	Mozilla Firefox/Thunderbird DOM Push Subscriptions Bypass (fixed in 159/153.6) Mitigation bypass in the DOM: Push Subscriptions component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117997	Oct 27, 2026	Firefox/Thunderbird Widget UAF sandbox escape (pre159) Sandbox escape due to use-after-free in the Widget component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117996	Oct 27, 2026	Firefox/Thunderbird WebRTC Boundary Check Bypass (pre159) Incorrect boundary conditions in the WebRTC component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117995	Oct 27, 2026	Firefox UI Events & Focus Handling PrivEsc (pre159) Privilege escalation in the DOM: UI Events & Focus Handling component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117994	Oct 27, 2026	Firefox/Thunderbird Use-After-Free in JS GC (fixed in 159, ESR 153.6) Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117993	Oct 27, 2026	Firefox/Thunderbird Text Component Integer Overflow (pre159) Integer overflow in the Graphics: Text component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117992	Oct 27, 2026	Mozilla Firefox/Thunderbird CSS Parser Info Disclosure (pre-159/115.44) Information disclosure in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117991	Oct 27, 2026	Firefox/Thunderbird Text & Fonts Layout OOB Boundary (pre 159) Incorrect boundary conditions in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117990	Oct 27, 2026	Mozilla Firefox/Thunderbird WebRender Sandbox Escape (pre159/153.6) Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117989	Oct 27, 2026	Firefox/Thunderbird Graphics UAF (fixed in 159, ESR 153.6) Use-after-free in the Graphics component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117988	Oct 27, 2026	Mozilla Firefox/Thunderbird CanvasWebGL Sandbox Escape (pre159/153.6) Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117986	Oct 27, 2026	Firefox/Thunderbird Graphics UAF (fixed in 159/153.6) Use-after-free in the Graphics component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117987	Oct 27, 2026	Mozilla Firefox/Thunderbird Graphics UAF before 159/153.6 Use-after-free in the Graphics component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117984	Oct 27, 2026	Firefox/Thunderbird Layout Scrolling & Overflow OOB before 159 Incorrect boundary conditions in the Layout: Scrolling and Overflow component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird
CVE-2026-117983	Oct 27, 2026	Firefox/Thunderbird Use-After-Free in Graphics (pre-159) Use-after-free in the Graphics component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.	Firefox Thunderbird