Issued at: 2026-04-07
Updated at: 2026-04-07
Synopsis
Important: firefox security update
Description
Mozilla Firefox is an open-source web browser, designed for standards compliance, performance, and portability.
Security Fix(es):
* firefox: thunderbird: Use-after-free in the JavaScript Engine component (CVE-2026-4701)
* firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149 (CVE-2026-4721)
* firefox: thunderbird: Privilege escalation in the Netmonitor component (CVE-2026-4717)
* firefox: thunderbird: Sandbox escape due to use-after-free in the Disability Access APIs component (CVE-2026-4688)
* firefox: thunderbird: Incorrect boundary conditions in the Graphics: Canvas2D component (CVE-2026-4706)
* firefox: thunderbird: Incorrect boundary conditions in the Audio/Video: Web Codecs component (CVE-2026-4695)
* firefox: thunderbird: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component (CVE-2026-4689)
* firefox: thunderbird: JIT miscompilation in the JavaScript Engine: JIT component (CVE-2026-4698)
* firefox: thunderbird: Incorrect boundary conditions, uninitialized memory in the JavaScript Engine component (CVE-2026-4716)
* firefox: thunderbird: Race condition, use-after-free in the Graphics: WebRender component (CVE-2026-4684)
* firefox: thunderbird: Undefined behavior in the WebRTC: Signaling component (CVE-2026-4705)
* firefox: thunderbird: Uninitialized memory in the Graphics: Canvas2D component (CVE-2026-4715)
* firefox: thunderbird: Incorrect boundary conditions in the Graphics: Canvas2D component (CVE-2026-4685)
* firefox: thunderbird: Incorrect boundary conditions in the Audio/Video component (CVE-2026-4714)
* firefox: thunderbird: Incorrect boundary conditions in the Audio/Video: GMP component (CVE-2026-4709)
* firefox: thunderbird: Incorrect boundary conditions in the Audio/Video component (CVE-2026-4710)
* firefox: thunderbird: Information disclosure in the Widget: Cocoa component (CVE-2026-4712)
* firefox: thunderbird: Incorrect boundary conditions in the Audio/Video: Web Codecs component (CVE-2026-4697)
* firefox: thunderbird: Incorrect boundary conditions in the Graphics component (CVE-2026-4713)
* firefox: thunderbird: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component (CVE-2026-4690)
* firefox: thunderbird: Use-after-free in the Widget: Cocoa component (CVE-2026-4711)
* firefox: thunderbird: Incorrect boundary conditions in the Graphics: Canvas2D component (CVE-2026-4686)
* firefox: thunderbird: Incorrect boundary conditions in the Graphics component (CVE-2026-4708)
* firefox: thunderbird: Use-after-free in the CSS Parsing and Computation component (CVE-2026-4691)
* firefox: thunderbird: Incorrect boundary conditions in the Layout: Text and Fonts component (CVE-2026-4699)
* firefox: thunderbird: Use-after-free in the Layout: Text and Fonts component (CVE-2026-4696)
* firefox: thunderbird: Incorrect boundary conditions in the Audio/Video: Playback component (CVE-2026-4693)
* firefox: thunderbird: Undefined behavior in the WebRTC: Signaling component (CVE-2026-4718)
* firefox: thunderbird: JIT miscompilation in the JavaScript Engine component (CVE-2026-4702)
* firefox: thunderbird: Incorrect boundary conditions in the Graphics: Text component (CVE-2026-4719)
* firefox: thunderbird: Incorrect boundary conditions, integer overflow in the Graphics component (CVE-2026-4694)
* firefox: thunderbird: Sandbox escape in the Responsive Design Mode component (CVE-2026-4692)
* firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149 (CVE-2026-4720)
* firefox: thunderbird: Mitigation bypass in the Networking: HTTP component (CVE-2026-4700)
* firefox: thunderbird: Incorrect boundary conditions in the Graphics: Canvas2D component (CVE-2026-4707)
* firefox: thunderbird: Denial-of-service in the WebRTC: Signaling component (CVE-2026-4704)
* firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the Telemetry component (CVE-2026-4687)
For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.