Firefox Developer Edition (en-US) 147.0
Firefox Developer Edition (en-US) 147.0, released December 22, 2025, fixes 18 CVEs in Firefox Developer Edition (en-US). None of them is reported as exploited. Patch Radar priority: Urgent. The latest Firefox Developer Edition (en-US) is 156.0, which also fixes every one of these CVEs.
Superseded. The latest Firefox Developer Edition (en-US) is 156.0, which also fixes every CVE on this page. Install that instead.
Priority of the 18 CVEs
Applies to
| Product | Version |
|---|---|
| Firefox Developer Edition (en-US) | 147.0 |
CVEs this fix closes
| Priority | CVE | Title | CVSS | EPSS | Exploitation |
|---|---|---|---|---|---|
| Urgent | CVE-2026-0892 | Memory safety bugs fixed in Firefox 147 and Thunderbird 147 | 9.8 | 0.0045 | None reported |
| Urgent | CVE-2026-0881 | Sandbox escape in the Messaging System component | 10.0 | 0.0035 | None reported |
| Urgent | CVE-2025-14860 | Use-after-free in the Disability Access APIs component | 9.8 | 0.0032 | None reported |
| High | CVE-2026-0880 | Sandbox escape due to integer overflow in the Graphics component | 8.8 | 0.0054 | None reported |
| High | CVE-2026-0879 | Sandbox escape due to incorrect boundary conditions in the Graphics component | 9.8 | 0.0050 | None reported |
| High | CVE-2026-0891 | Memory safety bugs fixed in Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147 | 8.1 | 0.0048 | None reported |
| High | CVE-2026-0877 | Mitigation bypass in the DOM: Security component | 8.1 | 0.0047 | None reported |
| High | CVE-2026-0878 | Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component | 8.0 | 0.0047 | None reported |
| High | CVE-2026-0882 | Use-after-free in the IPC component | 8.8 | 0.0047 | None reported |
| High | CVE-2026-0884 | Use-after-free in the JavaScript Engine component | 9.8 | 0.0046 | None reported |
| High | CVE-2026-0889 | Denial-of-service in the DOM: Service Workers component | 7.5 | 0.0046 | None reported |
| High | CVE-2026-0885 | Use-after-free in the JavaScript: GC component | 7.5 | 0.0040 | None reported |
| High | CVE-2026-0886 | Incorrect boundary conditions in the Graphics component | 7.5 | 0.0038 | None reported |
| High | CVE-2026-0883 | Information disclosure in the Networking component | 7.5 | 0.0036 | None reported |
| High | CVE-2026-0887 | Clickjacking issue, information disclosure in the PDF Viewer component | 7.5 | 0.0033 | None reported |
| High | CVE-2026-0890 | Spoofing issue in the DOM: Copy & Paste and Drag & Drop component | 7.5 | 0.0030 | None reported |
| High | CVE-2025-14861 | Memory safety bugs fixed in Firefox 146.0.1 | 8.8 | 0.0025 | None reported |
| Routine | CVE-2026-0888 | Information disclosure in the XML component | 5.3 | 0.0035 | None reported |
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