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CVE-2026-3473

Estado: AnalizadaAlta (7.1)—

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate file ownership and access control, which allows an authenticated user to access and download files belonging to other users or teams via crafted Boards API requests using valid file IDs.. Mattermost Advisory ID: MMSA-2026-00620

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/PR:L sin interacción: acceso remoto autenticado a servicios internos. Fallo de validación de propiedad en API permite lectura de archivos ajenos; CWE-639 es control de acceso fallido.

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 TrainingThreat Intelligence ProgramRestrict File and Directory PermissionsPrivileged Account ManagementPassword Policies

Tecnologías afectadas (1)

Mattermost — Mattermost Server

CWE

Referencias

JSON original (NVD)

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          "role": "CISA Coordinator",
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              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
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              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-05-22T12:12:41.198607Z"
        }
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      "tags": [
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      "source": "responsibledisclosure@mattermost.com",
      "description": [
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          "value": "CWE-639"
        }
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  "descriptions": [
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      "value": "Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate file ownership and access control, which allows an authenticated user to access and download files belonging to other users or teams via crafted Boards API requests using valid file IDs.. Mattermost Advisory ID: MMSA-2026-00620"
    },
    {
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      "value": "Las versiones de Mattermost 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 no validan la propiedad de los archivos y el control de acceso, lo que permite a un usuario autenticado acceder y descargar archivos pertenecientes a otros usuarios o equipos a través de solicitudes de la API de Boards manipuladas utilizando IDs de archivo válidos. ID de Aviso de Mattermost: MMSA-2026-00620"
    }
  ],
  "lastModified": "2026-07-23T16:10:00.137",
  "configurations": [
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