{"id":"CVE-2026-74989","title":"Internally found bugs fixed in Firefox 154","summary":"Internally found bugs present in Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability …","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","cvssSource":"adp","vendor":"Mozilla","product":"Firefox","affected":["Firefox","Thunderbird"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-08-20T15:50:43.213805Z"},"published":"2026-08-18","updated":"2026-10-28","sourceUpdated":"2026-10-28T16:36:02.550Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74989","references":[{"url":"https://bugzilla.mozilla.org/buglist.cgi?bug_id=2022257%2C2027351%2C2027380%2C2029289","label":"Low Severity internally found bugs fixed in Firefox 154"},{"url":"https://bugzilla.mozilla.org/buglist.cgi?bug_id=2027388%2C2029750%2C2029794%2C2043298%2C2045126%2C2049810%2C2051741","label":"Moderate Severity internally found bugs fixed in Firefox 154"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-74/"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-78/"}],"tags":["cve.org"],"epss":0.0057,"epssPercentile":0.4728,"ingestedAt":"2026-10-28T17:14:44.473Z","slug":"CVE-2026-74989","body":"## Overview\n\nInternally found bugs present in Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154 and Thunderbird 154.\n\n## Affected\n\n- `Firefox`\n- `Thunderbird`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}