# Firefox Developer Edition (de) 147.0

Firefox Developer Edition (de) 147.0, released December 22, 2025, fixes 18 CVEs in Firefox Developer Edition (de). None of them is reported as exploited. Patch Radar priority: Urgent. The latest Firefox Developer Edition (de) is 151.0, which also fixes every one of these CVEs.

- Web page: https://patchblox.com/security/fix/windows-app/mozilla.firefox.developeredition.de-147.0
- Platform: Windows apps
- Released: Dec 22, 2025
- Priority: Urgent (Closes CVE-2026-0892, rated Critical)
- CVEs: 18, exploited: 0, on CISA KEV: 0
- Superseded by: [Firefox Developer Edition (de) 151.0](https://patchblox.com/security/data/product/windows-app/firefox-developer-edition-de.md), the latest version, which also fixes every CVE listed here

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Firefox Developer Edition (de)](https://patchblox.com/security/data/product/windows-app/firefox-developer-edition-de.md) |  | 147.0 |

## CVEs this fix closes

| CVE | Priority | Title | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2026-0892](https://patchblox.com/security/data/cve/CVE-2026-0892.md) | Urgent | Memory safety bugs fixed in Firefox 147 and Thunderbird 147 | 9.8 | 0.0045 |  |
| [CVE-2026-0881](https://patchblox.com/security/data/cve/CVE-2026-0881.md) | Urgent | Sandbox escape in the Messaging System component | 10.0 | 0.0035 |  |
| [CVE-2025-14860](https://patchblox.com/security/data/cve/CVE-2025-14860.md) | Urgent | Use-after-free in the Disability Access APIs component | 9.8 | 0.0032 |  |
| [CVE-2026-0880](https://patchblox.com/security/data/cve/CVE-2026-0880.md) | High | Sandbox escape due to integer overflow in the Graphics component | 8.8 | 0.0054 |  |
| [CVE-2026-0879](https://patchblox.com/security/data/cve/CVE-2026-0879.md) | High | Sandbox escape due to incorrect boundary conditions in the Graphics component | 9.8 | 0.0050 |  |
| [CVE-2026-0891](https://patchblox.com/security/data/cve/CVE-2026-0891.md) | High | Memory safety bugs fixed in Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147 | 8.1 | 0.0048 |  |
| [CVE-2026-0877](https://patchblox.com/security/data/cve/CVE-2026-0877.md) | High | Mitigation bypass in the DOM: Security component | 8.1 | 0.0047 |  |
| [CVE-2026-0878](https://patchblox.com/security/data/cve/CVE-2026-0878.md) | High | Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component | 8.0 | 0.0047 |  |
| [CVE-2026-0882](https://patchblox.com/security/data/cve/CVE-2026-0882.md) | High | Use-after-free in the IPC component | 8.8 | 0.0047 |  |
| [CVE-2026-0884](https://patchblox.com/security/data/cve/CVE-2026-0884.md) | High | Use-after-free in the JavaScript Engine component | 9.8 | 0.0046 |  |
| [CVE-2026-0889](https://patchblox.com/security/data/cve/CVE-2026-0889.md) | High | Denial-of-service in the DOM: Service Workers component | 7.5 | 0.0046 |  |
| [CVE-2026-0885](https://patchblox.com/security/data/cve/CVE-2026-0885.md) | High | Use-after-free in the JavaScript: GC component | 7.5 | 0.0040 |  |
| [CVE-2026-0886](https://patchblox.com/security/data/cve/CVE-2026-0886.md) | High | Incorrect boundary conditions in the Graphics component | 7.5 | 0.0038 |  |
| [CVE-2026-0883](https://patchblox.com/security/data/cve/CVE-2026-0883.md) | High | Information disclosure in the Networking component | 7.5 | 0.0036 |  |
| [CVE-2026-0887](https://patchblox.com/security/data/cve/CVE-2026-0887.md) | High | Clickjacking issue, information disclosure in the PDF Viewer component | 7.5 | 0.0033 |  |
| [CVE-2026-0890](https://patchblox.com/security/data/cve/CVE-2026-0890.md) | High | Spoofing issue in the DOM: Copy & Paste and Drag & Drop component | 7.5 | 0.0030 |  |
| [CVE-2025-14861](https://patchblox.com/security/data/cve/CVE-2025-14861.md) | High | Memory safety bugs fixed in Firefox 146.0.1 | 8.8 | 0.0025 |  |
| [CVE-2026-0888](https://patchblox.com/security/data/cve/CVE-2026-0888.md) | Routine | Information disclosure in the XML component | 5.3 | 0.0035 |  |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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