« Volver al listado

CVE-2026-39971

Estado: AnalizadaAlta (7.2)—

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.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

AV:N/AC:L/PR:N: aplicación web expuesta que acepta cabecera Host controlada por atacante (T1190). Inyección SMTP permite spoofing de identidad y manipulación de cabeceras de correo (T1566.002: phishing via servidor de mail comprometido). Abuso de reputación del dominio legitimo (T1583.001).

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Vulnerability ScanningUser TrainingUser Account ManagementRestrict Web-Based ContentPrivileged Account ManagementNetwork Segmentation

Tecnologías afectadas (1)

S9Y — Serendipity

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "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."
    }
  ],
  "lastModified": "2026-06-17T10:42:50.143",
  "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"
}