Mozilla Firefox Open source web browser
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Recent Mozilla Firefox Security Advisories
| Advisory | Title | Published |
|---|---|---|
| mfsa2026-123 | Security Vulnerabilities fixed in Firefox 159.0.1 mfsa2026-123 | November 3, 2026 |
| mfsa2026-118 | Security Vulnerabilities fixed in Firefox 159 mfsa2026-118 | October 27, 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 |
| mfsa2026-117 | 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 |
| mfsa2026-113 | Security Vulnerabilities fixed in Firefox ESR 115.43.1 mfsa2026-113 | October 20, 2026 |
| mfsa2026-111 | Security Vulnerabilities fixed in Firefox 158.0.1 mfsa2026-111 | October 20, 2026 |
| mfsa2026-112 | Security Vulnerabilities fixed in Firefox ESR 153.5.1 mfsa2026-112 | October 20, 2026 |
| mfsa2026-108 | Security Vulnerabilities fixed in Firefox ESR 153.5 mfsa2026-108 | October 13, 2026 |
Known Exploited Mozilla Firefox Vulnerabilities
The following Mozilla Firefox vulnerabilities have been marked by CISA as Known to be Exploited by threat actors.
| Title | Description | Added |
|---|---|---|
| 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 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 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 |
The vulnerability CVE-2015-4495: Mozilla Firefox Security Feature Bypass Vulnerability is in the top 1% of the currently known exploitable vulnerabilities. 2 known exploited Mozilla Firefox vulnerabilities are in the top 5% (95th percentile or greater) of the EPSS exploit probability rankings.
EOL Dates
Ensure that you are using a supported version of Mozilla Firefox. Here are some end of life, and end of support dates for Mozilla Firefox.
| Release | EOL Date | Status |
|---|---|---|
| 159 | November 10, 2026 |
EOL This Year
Mozilla Firefox 159 will become EOL this year, in November 2026. |
| 158 | October 27, 2026 |
EOL
Mozilla Firefox 158 became EOL in 2026. |
| 157 | October 13, 2026 |
EOL
Mozilla Firefox 157 became EOL in 2026. |
| 156 | September 29, 2026 |
EOL
Mozilla Firefox 156 became EOL in 2026. |
| 155 | September 15, 2026 |
EOL
Mozilla Firefox 155 became EOL in 2026. |
| 154 | September 1, 2026 |
EOL
Mozilla Firefox 154 became EOL in 2026. |
| 153 | - |
Active
|
| 152 | July 21, 2026 |
EOL
Mozilla Firefox 152 became EOL in 2026. |
| 151 | June 16, 2026 |
EOL
Mozilla Firefox 151 became EOL in 2026. |
| 150 | May 18, 2026 |
EOL
Mozilla Firefox 150 became EOL in 2026. |
| 149 | April 21, 2026 |
EOL
Mozilla Firefox 149 became EOL in 2026. |
| 148 | March 24, 2026 |
EOL
Mozilla Firefox 148 became EOL in 2026. |
| 147 | February 24, 2026 |
EOL
Mozilla Firefox 147 became EOL in 2026. |
| 146 | January 13, 2026 |
EOL
Mozilla Firefox 146 became EOL in 2026. |
| 145 | December 9, 2025 |
EOL
Mozilla Firefox 145 became EOL in 2025. |
| 144 | November 11, 2025 |
EOL
Mozilla Firefox 144 became EOL in 2025. |
| 143 | October 14, 2025 |
EOL
Mozilla Firefox 143 became EOL in 2025. |
| 142 | September 16, 2025 |
EOL
Mozilla Firefox 142 became EOL in 2025. |
| 141 | August 19, 2025 |
EOL
Mozilla Firefox 141 became EOL in 2025. |
| 140 | September 29, 2026 |
EOL
Mozilla Firefox 140 became EOL in 2026. |
By the Year
In 2026 there have been 574 vulnerabilities in Mozilla Firefox with an average score of 7.8 out of ten. Last year, in 2025 Firefox had 189 security vulnerabilities published. That is, 385 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 | 574 | 7.84 |
| 2025 | 189 | 7.54 |
| 2024 | 190 | 7.15 |
| 2023 | 180 | 7.38 |
| 2022 | 159 | 7.44 |
| 2021 | 123 | 7.13 |
| 2020 | 148 | 7.27 |
| 2019 | 121 | 7.44 |
| 2018 | 312 | 7.82 |
It may take a day or so for new Firefox 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 Firefox Security Vulnerabilities
Firefox 159: Incorrect Boundary Conditions in Layout (Block & Inline)
CVE-2026-120572
8.8 - High
- November 03, 2026
Incorrect boundary conditions in the Layout: Block and Inline component. This vulnerability was fixed in Firefox 159.0.1.
Buffer Overflow
Frame poisoning in the Layout component
CVE-2026-118027
9.1 - Critical
- October 27, 2026
Frame poisoning in the Layout component. This vulnerability was fixed in Firefox ESR 115.44.
User Interface (UI) Misrepresentation of Critical Information
Use-after-free in the DOM: Core & HTML component
CVE-2026-117940
8.8 - High
- October 27, 2026
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the XML component
CVE-2026-117939
6.3 - Medium
- October 27, 2026
Use-after-free in the XML component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the DOM: Core & HTML component
CVE-2026-117936
8.8 - High
- October 27, 2026
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the Layout component
CVE-2026-117938
6.3 - Medium
- October 27, 2026
Use-after-free in the Layout component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Invalid pointer in the JavaScript Engine component
CVE-2026-117937
7.3 - High
- October 27, 2026
Invalid pointer in the JavaScript Engine component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Access of Uninitialized Pointer
Same-origin policy bypass in the CSS Parsing and Computation component
CVE-2026-117928
8.1 - High
- October 27, 2026
Same-origin policy bypass in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Origin Validation Error
Use-after-free in the DOM: Core & HTML component
CVE-2026-117929
8.8 - High
- October 27, 2026
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the DOM: Core & HTML component
CVE-2026-117925
8.8 - High
- October 27, 2026
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Incorrect boundary conditions in the SVG component
CVE-2026-117926
8.1 - High
- October 27, 2026
Incorrect boundary conditions in the SVG component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Buffer Overflow
Use-after-free in the SVG component
CVE-2026-117927
6.3 - Medium
- October 27, 2026
Use-after-free in the SVG component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the Audio/Video component
CVE-2026-117923
6.3 - Medium
- October 27, 2026
Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the XSLT component
CVE-2026-117924
6.3 - Medium
- October 27, 2026
Use-after-free in the XSLT component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the Networking: WebSockets component
CVE-2026-117922
8.8 - High
- October 27, 2026
Use-after-free in the Networking: WebSockets component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the CSS Parsing and Computation component
CVE-2026-117921
8.8 - High
- October 27, 2026
Use-after-free 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.
Dangling pointer
Use-after-free in the DOM: HTML Parser component
CVE-2026-117920
9.6 - Critical
- October 27, 2026
Use-after-free in the DOM: HTML Parser component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Invalid pointer in the Graphics: WebRender component
CVE-2026-117917
9.8 - Critical
- October 27, 2026
Invalid pointer in the Graphics: WebRender component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Access of Uninitialized Pointer
Use-after-free in the DOM: Core & HTML component
CVE-2026-117919
8.8 - High
- October 27, 2026
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the Graphics: Canvas2D component
CVE-2026-117918
8.8 - High
- October 27, 2026
Use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the SVG component
CVE-2026-117914
6.3 - Medium
- October 27, 2026
Use-after-free in the SVG component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Incorrect boundary conditions in the Layout: Block and Inline component
CVE-2026-117915
7.3 - High
- October 27, 2026
Incorrect boundary conditions in the Layout: Block and Inline component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Buffer Overflow
Use-after-free in the XSLT component
CVE-2026-117916
6.3 - Medium
- October 27, 2026
Use-after-free in the XSLT component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the SVG component
CVE-2026-117913
6.3 - Medium
- October 27, 2026
Use-after-free in the SVG component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Same-origin policy bypass in the CSS Parsing and Computation component
CVE-2026-117912
8.1 - High
- October 27, 2026
Same-origin policy bypass 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.
Origin Validation Error
Use-after-free in the JavaScript: GC component
CVE-2026-117909
6.3 - Medium
- October 27, 2026
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.
Dangling pointer
Invalid pointer in the JavaScript Engine component
CVE-2026-117910
7.3 - High
- October 27, 2026
Invalid pointer in the JavaScript Engine component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Access of Uninitialized Pointer
Use-after-free in the Audio/Video: Playback component
CVE-2026-117911
6.3 - Medium
- October 27, 2026
Use-after-free in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the Networking component
CVE-2026-117907
6.3 - Medium
- October 27, 2026
Use-after-free in the Networking component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the Graphics: ImageLib component
CVE-2026-117908
6.3 - Medium
- October 27, 2026
Use-after-free in the Graphics: ImageLib component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the CSS Parsing and Computation component
CVE-2026-117906
6.3 - Medium
- October 27, 2026
Use-after-free 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.
Dangling pointer
Use-after-free in the Audio/Video: Playback component
CVE-2026-117905
6.3 - Medium
- October 27, 2026
Use-after-free in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the JavaScript: GC component
CVE-2026-117904
8.8 - High
- October 27, 2026
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.
Dangling pointer
Use-after-free in the Audio/Video component
CVE-2026-117903
6.3 - Medium
- October 27, 2026
Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the Layout: Text and Fonts component
CVE-2026-117902
6.3 - Medium
- October 27, 2026
Use-after-free in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the DOM: Core & HTML component
CVE-2026-117901
8.8 - High
- October 27, 2026
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the DOM: Editor component
CVE-2026-117900
8.8 - High
- October 27, 2026
Use-after-free in the DOM: Editor component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the Networking: HTTP component
CVE-2026-117899
8.8 - High
- October 27, 2026
Use-after-free in the Networking: HTTP component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the JavaScript Engine: JIT component
CVE-2026-117898
6.3 - Medium
- October 27, 2026
Use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Incorrect boundary conditions in the Layout: Tables component
CVE-2026-117897
7.3 - High
- October 27, 2026
Incorrect boundary conditions in the Layout: Tables component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Buffer Overflow
Use-after-free in the DOM: Core & HTML component
CVE-2026-117896
6.3 - Medium
- October 27, 2026
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the DOM: Core & HTML component
CVE-2026-117895
6.3 - Medium
- October 27, 2026
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Incorrect boundary conditions in the Security: PSM component
CVE-2026-117893
5.4 - Medium
- October 27, 2026
Incorrect boundary conditions in the Security: PSM component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Buffer Overflow
Incorrect boundary conditions in the WebRTC: Signaling component
CVE-2026-117894
5.4 - Medium
- October 27, 2026
Incorrect boundary conditions in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Buffer Overflow
Privilege escalation due to use-after-free in the WebRTC: Networking component
CVE-2026-117892
7.3 - High
- October 27, 2026
Privilege escalation due to use-after-free in the WebRTC: Networking component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
Use-after-free in the JavaScript Engine: JIT component
CVE-2026-117891
7.3 - High
- October 27, 2026
Use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
JIT miscompilation in the JavaScript Engine: JIT component
CVE-2026-117890
7.3 - High
- October 27, 2026
JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Object Type Confusion
Uninitialized memory in the Graphics: Canvas2D component
CVE-2026-117888
5.4 - Medium
- October 27, 2026
Uninitialized memory in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Use of Uninitialized Variable
Incorrect boundary conditions in the JavaScript Engine component
CVE-2026-117889
7.3 - High
- October 27, 2026
Incorrect boundary conditions in the JavaScript Engine component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Buffer Overflow
Use-after-free in the DOM: Core & HTML component
CVE-2026-117887
8.8 - High
- October 27, 2026
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
Dangling pointer
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