{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-84640","assignerOrgId":"f16b083a-5664-49f3-a51e-8d479e5ed7fe","state":"PUBLISHED","assignerShortName":"mozilla","dateReserved":"2026-09-01T21:33:06.555Z","datePublished":"2026-09-01T21:33:06.832Z","dateUpdated":"2026-09-02T18:48:06.654Z"},"containers":{"cna":{"affected":[{"product":"Thunderbird","vendor":"Mozilla","versions":[{"status":"unaffected","version":"140.15","lessThanOrEqual":"140.*","versionType":"rpm"},{"status":"unaffected","version":"153.2","lessThanOrEqual":"153.*","versionType":"rpm"},{"status":"unaffected","version":"155","lessThanOrEqual":"*","versionType":"rpm"}]}],"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.","supportingMedia":[{"type":"text/html","base64":false,"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."}]}],"title":"One byte overflow read in mail parser","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/"}],"credits":[{"lang":"en","value":"Ramesh Adhikari, Dr. Faruk Kazi (CoE-CNDS Lab, VJTI, Mumbai, India)"}],"providerMetadata":{"orgId":"f16b083a-5664-49f3-a51e-8d479e5ed7fe","shortName":"mozilla","dateUpdated":"2026-09-01T21:44:15.623Z"}},"adp":[{"problemTypes":[{"descriptions":[{"type":"CWE","cweId":"CWE-126","lang":"en","description":"CWE-126 Buffer Over-read"}]}],"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"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-02T18:48:06.654Z"}}]}}