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CVE-2026-15341

Estado: AplazadaCrítica (9.8)—

The User Session Synchronizer plugin for WordPress is vulnerable to Authentication Bypass leading to Account Takeover in all versions up to, and including, 1.4.0. The `synchronize_session()` function, hooked on `init` and therefore executed on every request, performs no nonce, capability, or shared-secret validation against the attacker-supplied `ussync-key`, `ussync-token`, and `ussync-ref` parameters; when `ussync-key` references an unregistered slot, `get_option()` returns `false` for both the secret key and the domain list, causing the AES-256-CBC encryption key to degrade to the fully predictable `md5('')` and the referer allowlist to collapse to an empty-string match, while the AES IV is unconditionally hard-coded as `md5('another-secret')`. This makes it possible for unauthenticated attackers to supply a crafted request encrypting any known or guessable user email address in the `ussync-ref` parameter, causing the handler to call `wp_set_auth_cookie()` for the matched user and granting full authentication as that user — including administrators — with no prior knowledge of site secrets.

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.

Vulnerabilidad de bypass de autenticación en plugin WordPress expuesto en red pública sin autenticación (AV:N/PR:N/UI:N); permite al atacante obtener cookies de autenticación válidas para cualquier usuario, incluidos administradores, sin credenciales previas. CWE-287 confirma autenticación rota.

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

Privileged Account ManagementApplication Developer GuidanceActive Directory ConfigurationVulnerability ScanningUser TrainingUser Account Management

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

User Session Synchronizer — User Session SynchronizerAI

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-15341",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-15341",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-08-17T15:55:26.708943Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security@wordfence.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "security@wordfence.com",
      "affectedData": [
        {
          "vendor": "rafasashi",
          "product": "User Session Synchronizer",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "versionType": "semver",
              "lessThanOrEqual": "1.4.0"
            }
          ],
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-08-15T03:16:47.943",
  "references": [
    {
      "url": "https://plugins.trac.wordpress.org/browser/user-session-synchronizer/tags/1.4.0/includes/class-user-session-synchronizer.php#L117",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://plugins.trac.wordpress.org/browser/user-session-synchronizer/tags/1.4.0/includes/class-user-session-synchronizer.php#L286",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://plugins.trac.wordpress.org/browser/user-session-synchronizer/tags/1.4.0/includes/class-user-session-synchronizer.php#L310",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://plugins.trac.wordpress.org/browser/user-session-synchronizer/tags/1.4.0/includes/class-user-session-synchronizer.php#L422",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://plugins.trac.wordpress.org/browser/user-session-synchronizer/tags/1.4.0/includes/class-user-session-synchronizer.php#L598",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://plugins.trac.wordpress.org/browser/user-session-synchronizer/tags/1.4.0/includes/class-user-session-synchronizer.php#L631",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/cbc32e6d-47c5-4050-ba77-5a54203fe56a?source=cve",
      "source": "security@wordfence.com"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security@wordfence.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "The User Session Synchronizer plugin for WordPress is vulnerable to Authentication Bypass leading to Account Takeover in all versions up to, and including, 1.4.0. The `synchronize_session()` function, hooked on `init` and therefore executed on every request, performs no nonce, capability, or shared-secret validation against the attacker-supplied `ussync-key`, `ussync-token`, and `ussync-ref` parameters; when `ussync-key` references an unregistered slot, `get_option()` returns `false` for both the secret key and the domain list, causing the AES-256-CBC encryption key to degrade to the fully predictable `md5('')` and the referer allowlist to collapse to an empty-string match, while the AES IV is unconditionally hard-coded as `md5('another-secret')`. This makes it possible for unauthenticated attackers to supply a crafted request encrypting any known or guessable user email address in the `ussync-ref` parameter, causing the handler to call `wp_set_auth_cookie()` for the matched user and granting full authentication as that user — including administrators — with no prior knowledge of site secrets."
    }
  ],
  "lastModified": "2026-08-20T12:48:10.287",
  "sourceIdentifier": "security@wordfence.com"
}