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CVE-2026-42556

Estado: AnalizadaCrítica (9)—

Postiz is an AI social media scheduling tool. From version 2.21.6 to before version 2.21.7, any authenticated user who can create a post can store arbitrary HTML in post content by tampering their own save request and send the public preview link /p/<postId>?share=true to another user. The preview page renders that stored HTML with dangerouslySetInnerHTML on the main application origin. This issue has been patched in version 2.21.7.

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.

XSS almacenado (CWE-79) en vista previa compartida ejecuta JavaScript en navegador del usuario (dangerouslySetInnerHTML). Usuario autenticado crea contenido malicioso para robar sesiones o credenciales.

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

Restrict Web-Based ContentUser TrainingExecution PreventionBehavior Prevention on EndpointDisable or Remove Feature or ProgramApplication Isolation and Sandboxing

Tecnologías afectadas (1)

Gitroom — Postiz

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-42556",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
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        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-42556",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
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          ],
          "version": "2.0.3",
          "timestamp": "2026-05-13T17:24:41.066396Z"
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          "userInteraction": "REQUIRED",
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  "published": "2026-05-08T23:16:39.373",
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      "tags": [
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      "tags": [
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      "source": "security-advisories@github.com"
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  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
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      "source": "security-advisories@github.com",
      "description": [
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          "value": "CWE-79"
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      "value": "Postiz is an AI social media scheduling tool. From version 2.21.6 to before version 2.21.7, any authenticated user who can create a post can store arbitrary HTML in post content by tampering their own save request and send the public preview link /p/<postId>?share=true to another user. The preview page renders that stored HTML with dangerouslySetInnerHTML on the main application origin. This issue has been patched in version 2.21.7."
    },
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      "value": "Postiz es una herramienta de programación de redes sociales con IA. Desde la versión 2.21.6 hasta antes de la versión 2.21.7, cualquier usuario autenticado que puede crear una publicación puede almacenar HTML arbitrario en el contenido de la publicación manipulando su propia solicitud de guardado y enviar el enlace de vista previa pública /p/<postId>?share=true a otro usuario. La página de vista previa renderiza ese HTML almacenado con dangerouslySetInnerHTML en el origen principal de la aplicación. Este problema ha sido parcheado en la versión 2.21.7."
    }
  ],
  "lastModified": "2026-07-24T21:10:00.143",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
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