{"id":"CVE-2026-74986","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-74986","summary":"Site isolation issue in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.","details":"Site isolation issue in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.","published":"2026-08-18T13:17:40.433","modified":"2026-08-20T18:16:50.643","cvss":{"score":9.1,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":null,"references":[{"type":"WEB","url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2060048"},{"type":"WEB","url":"https://www.mozilla.org/security/advisories/mfsa2026-74/"},{"type":"WEB","url":"https://www.mozilla.org/security/advisories/mfsa2026-77/"},{"type":"WEB","url":"https://www.mozilla.org/security/advisories/mfsa2026-78/"},{"type":"WEB","url":"https://www.mozilla.org/security/advisories/mfsa2026-80/"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-08-20T18:16:50.643"}}