Mozilla Foundation Security Advisory 2026-32
Security Vulnerabilities fixed in Firefox ESR 140.10
- Announced
- April 21, 2026
- Impact
- high
- Products
- Firefox ESR
- Fixed in
-
- Firefox ESR 140.10
#CVE-2026-6746: Use-after-free in the DOM: Core & HTML component
- Reporter
- Evyatar Ben Asher, Keane Lucas, Nicholas Carlini, Newton Cheng, Daniel Freeman, Alex Gaynor, and Joel Weinberger using Claude from Anthropic
- Impact
- high
References
#CVE-2026-6747: Use-after-free in the WebRTC component
- Reporter
- Nan Wang
- Impact
- high
References
#CVE-2026-6748: Uninitialized memory in the Audio/Video: Web Codecs component
- Reporter
- Inseo An
- Impact
- high
References
#CVE-2026-6749: Information disclosure due to uninitialized memory in the Graphics: Canvas2D component
- Reporter
- Inseo An
- Impact
- high
References
#CVE-2026-6750: Privilege escalation in the Graphics: WebRender component
- Reporter
- choeseyeong
- Impact
- high
References
#CVE-2026-6751: Uninitialized memory in the Audio/Video: Web Codecs component
- Reporter
- Joren Afman
- Impact
- high
References
#CVE-2026-6752: Incorrect boundary conditions in the WebRTC component
- Reporter
- jmwebdevelopement
- Impact
- high
References
#CVE-2026-6753: Incorrect boundary conditions in the WebRTC component
- Reporter
- jmwebdevelopement
- Impact
- high
References
#CVE-2026-6754: Use-after-free in the JavaScript Engine component
- Reporter
- Xuehao Guo
- Impact
- high
References
#CVE-2026-6757: Invalid pointer in the JavaScript: WebAssembly component
- Reporter
- Evyatar Ben Asher, Keane Lucas, Nicholas Carlini, Newton Cheng, Daniel Freeman, Alex Gaynor, and Joel Weinberger using Claude from Anthropic
- Impact
- moderate
References
#CVE-2026-6759: Use-after-free in the Widget: Cocoa component
- Reporter
- Steven Michaud
- Impact
- moderate
References
#CVE-2026-6761: Privilege escalation in the Networking component
- Reporter
- kiyong
- Impact
- moderate
References
#CVE-2026-6762: Spoofing issue in the DOM: Core & HTML component
- Reporter
- Farras Givari
- Impact
- moderate
References
#CVE-2026-6763: Mitigation bypass in the File Handling component
- Reporter
- Tomoya Nakanishi
- Impact
- moderate
References
#CVE-2026-6764: Incorrect boundary conditions in the DOM: Device Interfaces component
- Reporter
- Florian
- Impact
- moderate
References
#CVE-2026-6765: Information disclosure in the Form Autofill component
- Reporter
- ABDULAZIZ ALASAIQAH
- Impact
- moderate
References
#CVE-2026-6766: Incorrect boundary conditions in the Libraries component in NSS
- Reporter
- Haruto Kimura
- Impact
- moderate
References
#CVE-2026-6767: Other issue in the Libraries component in NSS
- Reporter
- Haruto Kimura
- Impact
- moderate
References
#CVE-2026-6769: Privilege escalation in the Debugger component
- Reporter
- Tomoya Nakanishi
- Impact
- moderate
References
#CVE-2026-6770: Other issue in the Storage: IndexedDB component
- Reporter
- Dai
- Impact
- moderate
References
#CVE-2026-6771: Mitigation bypass in the DOM: Security component
- Reporter
- Rayhan Hanaputra
- Impact
- moderate
References
#CVE-2026-6772: Incorrect boundary conditions in the Libraries component in NSS
- Reporter
- sseehra
- Impact
- moderate
References
#CVE-2026-6776: Incorrect boundary conditions in the WebRTC: Networking component
- Reporter
- Nan Wang
- Impact
- low
References
#CVE-2026-6785: Memory safety bugs fixed in Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird ESR 140.10, Firefox 150 and Thunderbird 150
- Reporter
- Andrew McCreight, Ashley Zebrowski, Brian Grinstead, Christian Holler, Maurice Dauer, Tom Schuster and the Mozilla Fuzzing Team
- Impact
- high
Description
Memory safety bugs present in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149. 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.
References
#CVE-2026-6786: Memory safety bugs fixed in Firefox ESR 140.10, Thunderbird ESR 140.10, Firefox 150 and Thunderbird 150
- Reporter
- Alex Franchuk, Andrew McCreight, Brian Grinstead, Christian Holler, Jan de Mooij, Maurice Dauer, Sebastian Hengst, Tom Schuster and the Mozilla Fuzzing Team
- Impact
- high
Description
Memory safety bugs present in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149. 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.