Description
A use-after-free in FontFaceSet resulted in a potentially exploitable crash. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.
Affected products
mozilla: firefox
References8
- www.mozilla.org/security/advisories/mfsa2025-51/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2025-52/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2025-53/ Vendor Advisory
- bugzilla.mozilla.org/show_bug.cgi?id=1966423 Permissions Required
- www.mozilla.org/security/advisories/mfsa2025-54/
- www.mozilla.org/security/advisories/mfsa2025-55/
- lists.debian.org/debian-lts-announce/2025/06/msg00029.html
- lists.debian.org/debian-lts-announce/2025/07/msg00002.html
Metrics
- CVSS 3.1
-
9.8
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 8% percentile: 95 · as of 7 November 2026
- CWE
- CWE-416
Could this be exploited in your environment?
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