{"id":"CVE-2026-84640","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-84640","summary":"A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.","details":"A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.","published":"2026-09-01T22:17:19.800","modified":"2026-09-03T19:01:32.800","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":null,"references":[{"type":"WEB","url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2063964"},{"type":"ADVISORY","url":"https://www.mozilla.org/security/advisories/mfsa2026-86/"},{"type":"ADVISORY","url":"https://www.mozilla.org/security/advisories/mfsa2026-87/"},{"type":"ADVISORY","url":"https://www.mozilla.org/security/advisories/mfsa2026-88/"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-09-03T19:01:32.800"}}