CVE-2025-6425
The WebCompat WebExtension shipped with Firefox exposed a persistent UUID
CVSS Score
4.3
EPSS Score
0.0%
EPSS Percentile
0th
An attacker who enumerated resources from the WebCompat extension could have obtained a persistent UUID that identified the browser, and persisted between containers and normal/private browsing mode, but not profiles. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.
| Vendor | mozilla |
| Product | firefox |
| Ecosystems | |
| Industries | Technology |
| Published | Jun 24, 2025 |
| Last Updated | Apr 13, 2026 |
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Affected Versions
Mozilla / Firefox
All versions affected Mozilla / Thunderbird
All versions affected References
bugzilla.mozilla.org: https://bugzilla.mozilla.org/show_bug.cgi?id=1717672 mozilla.org: https://www.mozilla.org/security/advisories/mfsa2025-51/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2025-52/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2025-53/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2025-54/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2025-55/ lists.debian.org: https://lists.debian.org/debian-lts-announce/2025/07/msg00002.html lists.debian.org: https://lists.debian.org/debian-lts-announce/2025/06/msg00029.html
Credits
Rob Wu