Mozilla Firefox vulnerabilities

CVE-2026-5734 [CRITICAL] CWE-787 CVE-2026-5734: Memory safety bugs present in Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thun Memory safety bugs present in Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thunderbird 149.0.1. 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. This vulnerability was fixed in Firefox 149.0.2, Firefox ESR 140.9.1, Thunde

CVE-2026-5735 [CRITICAL] CWE-787 CVE-2026-5735: Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. Some of these bugs showed evi Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. 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. This vulnerability was fixed in Firefox 149.0.2 and Thunderbird 149.0.2.

CVE-2026-5732 [HIGH] CWE-190 CVE-2026-5732: Incorrect boundary conditions, integer overflow in the Graphics: Text component. This vulnerability Incorrect boundary conditions, integer overflow in the Graphics: Text component. This vulnerability was fixed in Firefox 149.0.2, Firefox ESR 140.9.1, Thunderbird 149.0.2, and Thunderbird 140.9.1.

CVE-2026-5733 [HIGH] CWE-119 CVE-2026-5733: Incorrect boundary conditions in the Graphics: WebGPU component. This vulnerability was fixed in Fir Incorrect boundary conditions in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 149.0.2 and Thunderbird 149.0.2.

CVE-2026-4701 [CRITICAL] CWE-416 CVE-2026-4701: Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Fire Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVE-2026-4725 [CRITICAL] CWE-416 CVE-2026-4725: Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fix Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 149 and Thunderbird 149.

CVE-2026-4689 [CRITICAL] CWE-190 CVE-2026-4689: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This v Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVE-2026-4688 [CRITICAL] CWE-416 CVE-2026-4688: Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVE-2026-4711 [CRITICAL] CWE-416 CVE-2026-4711: Use-after-free in the Widget: Cocoa component. This vulnerability was fixed in Firefox 149, Firefox Use-after-free in the Widget: Cocoa component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVE-2026-4702 [CRITICAL] CWE-843 CVE-2026-4702: JIT miscompilation in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, JIT miscompilation in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVE-2026-4710 [CRITICAL] CWE-119 CVE-2026-4710: Incorrect boundary conditions in the Audio/Video component. This vulnerability was fixed in Firefox Incorrect boundary conditions in the Audio/Video component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVE-2026-4692 [CRITICAL] CVE-2026-4692: Sandbox escape in the Responsive Design Mode component. This vulnerability was fixed in Firefox 149, Sandbox escape in the Responsive Design Mode component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVE-2026-4715 [CRITICAL] CWE-908 CVE-2026-4715: Uninitialized memory in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 14 Uninitialized memory in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVE-2026-4723 [CRITICAL] CWE-416 CVE-2026-4723: Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149 and T Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149 and Thunderbird 149.

CVE-2026-4691 [CRITICAL] CWE-416 CVE-2026-4691: Use-after-free in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox Use-after-free in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVE-2026-4729 [CRITICAL] CWE-120 CVE-2026-4729: Memory safety bugs present in Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of Memory safety bugs present in Firefox 148 and Thunderbird 148. 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. This vulnerability was fixed in Firefox 149 and Thunderbird 149.

CVE-2026-4696 [CRITICAL] CWE-416 CVE-2026-4696: Use-after-free in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 149, Use-after-free in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVE-2026-4705 [CRITICAL] CWE-758 CVE-2026-4705: Undefined behavior in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 149, Undefined behavior in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVE-2026-4698 [CRITICAL] CWE-843 CVE-2026-4698: JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVE-2026-4717 [CRITICAL] CVE-2026-4717: Privilege escalation in the Netmonitor component. This vulnerability was fixed in Firefox 149, Firef Privilege escalation in the Netmonitor component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.