{"id":"CVE-2025-6424","title":"A use-after-free in FontFaceSet resulted in a potentially exploitable crash","summary":"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.","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-416"],"vendor":"mozilla","product":"firefox","affected":["firefox < 115.25.0","firefox < 140.0","firefox >= 116.0, < 128.12.0"],"patched":["firefox 128.12.0"],"published":"2025-06-24","updated":"2026-09-30","sourceUpdated":"2026-09-30T18:10:00.190","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-6424","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1966423","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-51/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-52/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-53/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-54/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-55/","label":"security@mozilla.org"},{"url":"https://lists.debian.org/debian-lts-announce/2025/06/msg00029.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2025/07/msg00002.html","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.0439,"epssPercentile":0.90986,"ingestedAt":"2026-09-30T18:17:24.442Z","slug":"CVE-2025-6424","body":"## Overview\n\nA 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.\n\n## Affected\n\n- `firefox < 115.25.0`\n- `firefox < 140.0`\n- `firefox >= 116.0, < 128.12.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `firefox 128.12.0`","depth":"midnight","depthScore":55,"depthScoreParts":{"impact":53.9,"likelihood":0.9,"exploitation":0,"ransomware":0},"changes":[]}