CVE-2025-6424

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

9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

8.0% chance of exploitation in the next 30 days; higher than 94% of CVEs (scores of 2026-10-25)

CWE

CWE-416

Published

2025-06-24

Modified

2026-10-23

Record from

the NVD, synced 2026-10-24

Affected

• mozilla:firefox

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1966423
• https://www.mozilla.org/security/advisories/mfsa2025-51/
• https://www.mozilla.org/security/advisories/mfsa2025-52/
• https://www.mozilla.org/security/advisories/mfsa2025-53/
• https://www.mozilla.org/security/advisories/mfsa2025-54/

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