{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63435","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-07-16T19:35:57.767Z","datePublished":"2026-09-01T20:09:20.820Z","dateUpdated":"2026-09-02T15:44:56.368Z"},"containers":{"cna":{"title":"Mail: Email address spoofing via malformed RFC 2047 encoded-words","problemTypes":[{"descriptions":[{"cweId":"CWE-436","lang":"en","description":"CWE-436: Interpretation Conflict","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.3,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","version":"3.1"}}],"references":[{"name":"https://github.com/mikel/mail/security/advisories/GHSA-mvxr-6m87-mv2q","tags":["x_refsource_CONFIRM"],"url":"https://github.com/mikel/mail/security/advisories/GHSA-mvxr-6m87-mv2q"},{"name":"https://github.com/mikel/mail/pull/1664","tags":["x_refsource_MISC"],"url":"https://github.com/mikel/mail/pull/1664"},{"name":"https://github.com/mikel/mail/commit/f9d59c2e447af42e2c3dec5a56b1bb25c7292859","tags":["x_refsource_MISC"],"url":"https://github.com/mikel/mail/commit/f9d59c2e447af42e2c3dec5a56b1bb25c7292859"},{"name":"https://github.com/mikel/mail/releases/tag/2.9.1","tags":["x_refsource_MISC"],"url":"https://github.com/mikel/mail/releases/tag/2.9.1"}],"affected":[{"vendor":"mikel","product":"mail","versions":[{"version":"< 2.9.1","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-09-01T20:09:20.820Z"},"descriptions":[{"lang":"en","value":"Mail is an internet library for Ruby designed to handle email generation, parsing, and sending. Prior to 2.9.1, Mail::Utilities.q_value_decode and Mail::Utilities.b_value_decode used a single String#match and an overly greedy charset capture to decode only the first RFC 2047 encoded-word and mishandle surrounding or subsequent text. A crafted malformed encoded-word in an address display name or local part could cross ? delimiters and make decoded From, To, or Reply-To header values differ from the raw values inspected by a human reviewer or downstream parser, enabling apparent sender or recipient spoofing, phishing, or authorization-check bypass. This issue is fixed in version 2.9.1."}],"source":{"advisory":"GHSA-mvxr-6m87-mv2q","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-02T15:44:44.094469Z","id":"CVE-2026-63435","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":"2026-09-02T15:44:56.368Z"}}]}}