VulnerabilityModified
CVE-2025-6424
A use-after-free in FontFaceSet resulted in a potentially exploitable crash.
CRITICAL 9.8EPSS 3.41%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (3.41%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 3.41% probability · 88th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- mozilla/firefox
- Source
- security@mozilla.org
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1966423Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2025-51/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2025-52/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2025-53/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2025-54/
- https://www.mozilla.org/security/advisories/mfsa2025-55/
- https://lists.debian.org/debian-lts-announce/2025/06/msg00029.html
- https://lists.debian.org/debian-lts-announce/2025/07/msg00002.html
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.