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CVE-2026-49952

Estado: AplazadaCrítica (9.3)—

Discuz! X5.0 releases 20260320 through 20260501 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to gain unauthorized access to database backup and restore functionality by exploiting a shared cryptographic key between UCenter integration and the database backup API exposed by dbbak.php. Attackers can inject a crafted payload through the username parameter during login to abuse the encryption oracle in logging_ctl::logging_more(), obtain a legitimately signed token, and use it to bypass authorization for database export and import operations, with the additional ability to trigger a race condition to impersonate arbitrary users.

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.

Acceso remoto sin autenticación a aplicación web expuesta (T1190). Explotación de clave criptográfica compartida permite obtener token válido (T1078.001), manipular datos de BD (T1565.001) y extraer backups (T1005).

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 ScanningRestrict File and Directory PermissionsPrivileged Account ManagementPassword PoliciesRemote Data StorageNetwork Segmentation

Tecnologías afectadas (1)

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

Discuz — Discuz X5AI

CWE

Referencias

JSON original (NVD)

Mostrar
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  "id": "CVE-2026-49952",
  "cveTags": [],
  "metrics": {
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        "ssvcData": {
          "id": "CVE-2026-49952",
          "role": "CISA Coordinator",
          "options": [
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              "exploitation": "poc"
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            {
              "automatable": "yes"
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            {
              "technicalImpact": "total"
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          "version": "2.0.3",
          "timestamp": "2026-06-15T19:58:52.987295Z"
        }
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    "cvssMetricV31": [
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          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
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          "Recovery": "NOT_DEFINED",
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          "Automatable": "NOT_DEFINED",
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "valueDensity": "NOT_DEFINED",
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          "modifiedAttackVector": "NOT_DEFINED",
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          "vulnAvailabilityImpact": "NONE",
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          "modifiedUserInteraction": "NOT_DEFINED",
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          "modifiedAttackRequirements": "NOT_DEFINED",
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          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
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          "repo": "https://gitee.com/Discuz/DiscuzX",
          "vendor": "Discuz!",
          "product": "Discuz! X5.0",
          "versions": [
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              "status": "affected",
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              "versionType": "date",
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  "published": "2026-06-15T20:16:29.103",
  "references": [
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    {
      "url": "https://karmainsecurity.com/KIS-2026-09",
      "source": "disclosure@vulncheck.com"
    },
    {
      "url": "https://karmainsecurity.com/chaining-bugs-in-discuz-from-race-condition-to-rce",
      "source": "disclosure@vulncheck.com"
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      "url": "https://www.vulncheck.com/advisories/discuz-x5-0-authentication-bypass-via-dbbak-php-encryption-oracle",
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      "lang": "en",
      "value": "Discuz! X5.0 releases 20260320 through 20260501 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to gain unauthorized access to database backup and restore functionality by exploiting a shared cryptographic key between UCenter integration and the database backup API exposed by dbbak.php. Attackers can inject a crafted payload through the username parameter during login to abuse the encryption oracle in logging_ctl::logging_more(), obtain a legitimately signed token, and use it to bypass authorization for database export and import operations, with the additional ability to trigger a race condition to impersonate arbitrary users."
    }
  ],
  "lastModified": "2026-06-17T10:55:48.613",
  "sourceIdentifier": "disclosure@vulncheck.com"
}