{"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": "2026-09-01T20:09:20.820Z"}, "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"}}}}

{}

{"affected": [{"affectedData": [{"product": "mail", "vendor": "mikel", "versions": [{"status": "affected", "version": "< 2.9.1"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "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."}], "id": "CVE-2026-63435", "lastModified": "2026-09-01T21:18:35.287", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 3.9, "impactScore": 1.4, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-09-01T21:18:35.287", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/mikel/mail/commit/f9d59c2e447af42e2c3dec5a56b1bb25c7292859"}, {"source": "security-advisories@github.com", "url": "https://github.com/mikel/mail/pull/1664"}, {"source": "security-advisories@github.com", "url": "https://github.com/mikel/mail/releases/tag/2.9.1"}, {"source": "security-advisories@github.com", "url": "https://github.com/mikel/mail/security/advisories/GHSA-mvxr-6m87-mv2q"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-436"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{}