Firefox Developer Edition (ach) 149.0
Firefox Developer Edition (ach) 149.0, released March 13, 2026, fixes 47 CVEs in Firefox Developer Edition (ach). None of them is reported as exploited. Patch Radar priority: Urgent. The latest Firefox Developer Edition (ach) is 151.0, which also fixes every one of these CVEs.
Superseded. The latest Firefox Developer Edition (ach) is 151.0, which also fixes every CVE on this page. Install that instead.
Priority of the 47 CVEs
Applies to
| Product | Version |
|---|---|
| Firefox Developer Edition (ach) | 149.0 |
CVEs this fix closes
| Priority | CVE | Title | CVSS | EPSS | Exploitation |
|---|---|---|---|---|---|
| Urgent | CVE-2026-4723 | Use-after-free in the JavaScript Engine component | 9.8 | 0.0062 | None reported |
| Urgent | CVE-2026-4724 | Undefined behavior in the Audio/Video component | 9.1 | 0.0051 | None reported |
| Urgent | CVE-2026-4729 | Memory safety bugs fixed in Firefox 149 and Thunderbird 149 | 9.8 | 0.0034 | None reported |
| Urgent | CVE-2026-4725 | Sandbox escape due to use-after-free in the Graphics: Canvas2D component | 10.0 | 0.0033 | None reported |
| High | CVE-2026-4696 | Use-after-free in the Layout: Text and Fonts component | 9.8 | 0.0097 | None reported |
| High | CVE-2026-4700 | Mitigation bypass in the Networking: HTTP component | 9.8 | 0.0092 | None reported |
| High | CVE-2026-4690 | Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component | 8.6 | 0.0080 | None reported |
| High | CVE-2026-4694 | Incorrect boundary conditions, integer overflow in the Graphics component | 8.2 | 0.0080 | None reported |
| High | CVE-2026-4698 | JIT miscompilation in the JavaScript Engine: JIT component | 9.8 | 0.0079 | None reported |
| High | CVE-2026-4686 | Incorrect boundary conditions in the Graphics: Canvas2D component | 8.2 | 0.0073 | None reported |
| High | CVE-2026-4685 | Incorrect boundary conditions in the Graphics: Canvas2D component | 8.2 | 0.0071 | None reported |
| High | CVE-2026-4693 | Incorrect boundary conditions in the Audio/Video: Playback component | 8.2 | 0.0071 | None reported |
| High | CVE-2026-4695 | Incorrect boundary conditions in the Audio/Video: Web Codecs component | 8.2 | 0.0071 | None reported |
| High | CVE-2026-4697 | Incorrect boundary conditions in the Audio/Video: Web Codecs component | 8.2 | 0.0071 | None reported |
| High | CVE-2026-4699 | Incorrect boundary conditions in the Layout: Text and Fonts component | 8.2 | 0.0071 | None reported |
| High | CVE-2026-4702 | JIT miscompilation in the JavaScript Engine component | 9.8 | 0.0070 | None reported |
| High | CVE-2026-4689 | Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component | 10.0 | 0.0069 | None reported |
| High | CVE-2026-4705 | Undefined behavior in the WebRTC: Signaling component | 9.8 | 0.0066 | None reported |
| High | CVE-2026-4704 | Denial-of-service in the WebRTC: Signaling component | 8.2 | 0.0065 | None reported |
| High | CVE-2026-4707 | Incorrect boundary conditions in the Graphics: Canvas2D component | 8.2 | 0.0060 | None reported |
| High | CVE-2026-4687 | Sandbox escape due to incorrect boundary conditions in the Telemetry component | 8.6 | 0.0056 | None reported |
| High | CVE-2026-4688 | Sandbox escape due to use-after-free in the Disability Access APIs component | 10.0 | 0.0055 | None reported |
| High | CVE-2026-4726 | Denial-of-service in the XML component | 7.5 | 0.0055 | None reported |
| High | CVE-2026-4727 | Denial-of-service in the Libraries component in NSS | 7.5 | 0.0055 | None reported |
| High | CVE-2026-4692 | Sandbox escape in the Responsive Design Mode component | 10.0 | 0.0051 | None reported |
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