CVE-2026-41319

{"id": "CVE-2026-41319", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-41319", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-04-25T01:46:14.462850Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 2.8}, {"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.9, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 2.2}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "jstedfast", "product": "MailKit", "versions": [{"status": "affected", "version": "< 4.16.0"}]}]}], "published": "2026-04-24T04:16:20.400", "references": [{"url": "https://github.com/jstedfast/MailKit/security/advisories/GHSA-9j88-vvj5-vhgr", "tags": ["Exploit", "Vendor Advisory"], "source": "security-advisories@github.com"}, {"url": "https://github.com/jstedfast/MailKit/security/advisories/GHSA-9j88-vvj5-vhgr", "tags": ["Exploit", "Vendor Advisory"], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-74"}]}], "descriptions": [{"lang": "en", "value": "MailKit is a cross-platform mail client library built on top of MimeKit. A STARTTLS Response Injection vulnerability in versions prior to 4.16.0 allows a Man-in-the-Middle attacker to inject arbitrary protocol responses across the plaintext-to-TLS trust boundary, enabling SASL authentication mechanism downgrade (e.g., forcing PLAIN instead of SCRAM-SHA-256). The internal read buffer in `SmtpStream`, `ImapStream`, and `Pop3Stream` is not flushed when the underlying stream is replaced with `SslStream` during STARTTLS upgrade, causing pre-TLS attacker-injected data to be processed as trusted post-TLS responses. Version 4.16.0 patches the issue."}, {"lang": "es", "value": "MailKit es una biblioteca de cliente de correo multiplataforma construida sobre MimeKit. Una vulnerabilidad de inyecci\u00f3n de respuesta STARTTLS en versiones anteriores a la 4.16.0 permite a un atacante man-in-the-middle inyectar respuestas de protocolo arbitrarias a trav\u00e9s del l\u00edmite de confianza de texto plano a TLS, lo que permite la degradaci\u00f3n del mecanismo de autenticaci\u00f3n SASL (por ejemplo, forzar PLAIN en lugar de SCRAM-SHA-256). El b\u00fafer de lectura interno en \u2019SmtpStream\u2019, \u2019ImapStream\u2019 y \u2019Pop3Stream\u2019 no se vac\u00eda cuando el flujo subyacente es reemplazado con \u2019SslStream\u2019 durante la actualizaci\u00f3n STARTTLS, lo que hace que los datos inyectados por el atacante pre-TLS sean procesados como respuestas post-TLS confiables. La versi\u00f3n 4.16.0 corrige el problema."}], "lastModified": "2026-10-26T22:10:00.163", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:jstedfast:mailkit:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "93C4C88D-7A8F-468C-90DE-0BBD8B916D6A", "versionEndExcluding": "4.16.0"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}