CVE-2026-39971

{"id": "CVE-2026-39971", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-39971", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-04-15T16:20:55.327550Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 7.2, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}, "impactScore": 2.7, "exploitabilityScore": 3.9}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "s9y", "product": "Serendipity", "versions": [{"status": "affected", "version": "< 2.6.0"}]}]}], "published": "2026-04-15T04:17:39.763", "references": [{"url": "https://github.com/s9y/Serendipity/releases/tag/2.6.0", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/s9y/Serendipity/security/advisories/GHSA-458g-q4fh-mj6r", "tags": ["Exploit", "Mitigation", "Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-113"}]}], "descriptions": [{"lang": "en", "value": "Serendipity is a PHP-powered weblog engine. In versions 2.6-beta2 and below, the email sending functionality in include/functions.inc.php inserts $_SERVER['HTTP_HOST'] directly into the Message-ID SMTP header without validation, and the existing sanitization function serendipity_isResponseClean() is not called on HTTP_HOST before embedding it. An attacker who can control the Host header during an email-triggering action such as comment notifications or subscription emails can inject arbitrary SMTP headers into outgoing emails. This enables identity spoofing, reply hijacking via manipulated Message-ID threading, and email reputation abuse through the attacker's domain being embedded in legitimate mail headers. This issue has been fixed in version 2.6.0."}, {"lang": "es", "value": "Serendipity es un motor de weblog impulsado por PHP. En las versiones 2.6-beta2 e inferiores, la funcionalidad de env\u00edo de correo electr\u00f3nico en include/functions.inc.php inserta $_SERVER[\u2019HTTP_HOST\u2019] directamente en el encabezado SMTP Message-ID sin validaci\u00f3n, y la funci\u00f3n de saneamiento existente serendipity_isResponseClean() no se llama en HTTP_HOST antes de incrustarlo. Un atacante que puede controlar el encabezado Host durante una acci\u00f3n que desencadena un correo electr\u00f3nico, como notificaciones de comentarios o correos electr\u00f3nicos de suscripci\u00f3n, puede inyectar encabezados SMTP arbitrarios en los correos electr\u00f3nicos salientes. Esto permite la suplantaci\u00f3n de identidad, el secuestro de respuestas a trav\u00e9s de la manipulaci\u00f3n del encadenamiento de Message-ID, y el abuso de la reputaci\u00f3n del correo electr\u00f3nico a trav\u00e9s del dominio del atacante incrustado en los encabezados de correo leg\u00edtimos. Este problema ha sido solucionado en la versi\u00f3n 2.6.0."}], "lastModified": "2026-10-26T22:10:00.163", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:s9y:serendipity:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "25355E06-ECC8-4A6C-ADB1-1A8ED17E5ABF", "versionEndExcluding": "2.6.0"}, {"criteria": "cpe:2.3:a:s9y:serendipity:2.6.0:beta1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "D31C5F34-5B83-4955-870B-0D1AC375DA24"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}