{"id":"CVE-2026-84640","state":"PUBLISHED","title":"One byte overflow read in mail parser","description":"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.","publishedAt":"2026-09-01T21:33:06.832Z","updatedAt":"2026-09-02T18:48:06.654Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","source":"CISA-ADP"},"assigner":"mozilla","products":["Mozilla Thunderbird"],"affected":[{"vendor":"Mozilla","product":"Thunderbird","versions":[{"version":"140.15","status":"unaffected","lessThanOrEqual":"140.*","versionType":"rpm"},{"version":"153.2","status":"unaffected","lessThanOrEqual":"153.*","versionType":"rpm"},{"version":"155","status":"unaffected","lessThanOrEqual":"*","versionType":"rpm"}]}],"references":["https://bugzilla.mozilla.org/show_bug.cgi?id=2063964","https://www.mozilla.org/security/advisories/mfsa2026-86/","https://www.mozilla.org/security/advisories/mfsa2026-87/","https://www.mozilla.org/security/advisories/mfsa2026-88/"],"weaknesses":["CWE-126"],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/84xxx/CVE-2026-84640.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-84640","state":"PUBLISHED","datePublished":"2026-09-01T21:33:06.832Z","dateUpdated":"2026-09-02T18:48:06.654Z","assignerShortName":"mozilla","assignerOrgId":"f16b083a-5664-49f3-a51e-8d479e5ed7fe","dateReserved":"2026-09-01T21:33:06.555Z"},"containers":{"cna":{"title":"One byte overflow read in mail parser","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Mozilla","product":"Thunderbird","versions":[{"version":"140.15","status":"unaffected","lessThanOrEqual":"140.*","versionType":"rpm"},{"version":"153.2","status":"unaffected","lessThanOrEqual":"153.*","versionType":"rpm"},{"version":"155","status":"unaffected","lessThanOrEqual":"*","versionType":"rpm"}]}],"references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2063964"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-86/"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-87/"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-88/"}],"providerMetadata":{"shortName":"mozilla","orgId":"f16b083a-5664-49f3-a51e-8d479e5ed7fe","dateUpdated":"2026-09-01T21:44:15.623Z"},"credits":[{"lang":"en","value":"Ramesh Adhikari, Dr. Faruk Kazi (CoE-CNDS Lab, VJTI, Mumbai, India)"}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":7.5,"attackVector":"NETWORK","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-09-02T18:47:36.596726Z","id":"CVE-2026-84640","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-126","type":"CWE","lang":"en","description":"CWE-126 Buffer Over-read"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-02T18:48:06.654Z"}}]}}}