{"id":"CVE-2026-109749","title":"Use-after-free in the JavaScript: WebAssembly component","summary":"Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.","severity":"medium","cvss":5.4,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N","cwe":["CWE-416"],"published":"2026-10-13","updated":"2026-10-13","sourceUpdated":"2026-10-13T19:18:39.043","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-109749","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2067174","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-106/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-109/","label":"security@mozilla.org"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-10-13T13:27:04.006Z","vendor":"Mozilla","product":"Firefox","affected":["Firefox","Thunderbird"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-13T14:13:35.851244Z"},"slug":"CVE-2026-109749","body":"## Overview\n\nUse-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":29.7,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":219765,"id":"CVE-2026-109749","ts":1791905696491,"field":"cvss","old":null,"new":"5.4"},{"seq":219764,"id":"CVE-2026-109749","ts":1791905696491,"field":"severity","old":"none","new":"medium"}]}