{"id":"CVE-2026-4701","published":"2026-03-24T12:30:29Z","modified":"2026-05-12T16:54:17Z","title":"Use-after-free in the JavaScript Engine component","vendor":"Mozilla","product":"Firefox","tier":"tail","description":{"text":"Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.","provenance":"source","from":"CVE.org"},"cvss":{"score":9.8,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"CISA ADP Vulnrichment"},"epss":{"score":0.00478,"percentile":0.41183,"provenance":"source"},"cwes":[{"id":"CWE-416","name":"Use After Free"}],"references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2009303","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-20/","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-22/","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-23/","tags":[]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-24/","tags":[]}],"priority":{"score":15.1,"factors":[{"name":"EPSS percentile","points":8.24},{"name":"CVSS severity","points":6.86}]},"vendorSlug":"mozilla","euvd":{"id":"EUVD-2026-14819","exploited":false,"provenance":"source"},"lineage":{"familyId":"fam-class-mozilla-firefox-cwe-416"}}