{"id":"CVE-2026-100778","published":"2026-09-29T12:36:05Z","modified":"2026-09-30T17:20:18Z","title":"Sandbox escape due to use-after-free in the DOM: Core & HTML component","vendor":"Mozilla","product":"Firefox","tier":"tail","description":{"text":"Sandbox escape due to use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.","provenance":"source","from":"CVE.org"},"cvss":{"score":9.6,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","provenance":"source","from":"CISA ADP Vulnrichment"},"epss":{"score":0.00319,"percentile":0.24861,"provenance":"source"},"cwes":[{"id":"CWE-416","name":"Use After Free"}],"references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2068406","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-100/","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-101/","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-102/","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-103/","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-97/","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-98/","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-99/","tags":[]}],"priority":{"score":11.7,"factors":[{"name":"EPSS percentile","points":4.97},{"name":"CVSS severity","points":6.72}]},"vendorSlug":"mozilla","euvd":{"id":"EUVD-2026-88930","exploited":false,"provenance":"source"},"lineage":{"familyId":"fam-class-mozilla-firefox-cwe-416"}}