{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "10.11.0"
              },
              {
                "fixed": "10.11.15"
              },
              {
                "introduced": "11.4.0"
              },
              {
                "fixed": "11.4.5"
              },
              {
                "introduced": "11.5.0"
              },
              {
                "fixed": "11.5.4"
              },
              {
                "introduced": "11.6.0"
              },
              {
                "fixed": "11.6.1"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "5b955468ea1ea8b56c0fb10feb258a36a767d7bb"
            },
            {
              "fixed": "f6760151c4a7b4b9d0807fa18892aaf24a3e190e"
            },
            {
              "introduced": "2a1ac98bd3fae587927adf9340ba266c8c02018e"
            },
            {
              "fixed": "292d4b7ea15b49a29989129758f25be37aec946e"
            },
            {
              "introduced": "9f2616376582893035a7e3cb38b0fab648bba4e8"
            },
            {
              "fixed": "fff6ab3a5851dc47c65bd636281f5c678fe9de25"
            },
            {
              "introduced": "d4f4e78835e86e2e76f76bfe797623076f5c9835"
            },
            {
              "fixed": "ffee10a61081dcc058f92fe65ba138804c3ca73b"
            }
          ],
          "repo": "https://github.com/mattermost/mattermost",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Mattermost",
    "cwe_ids": [
      "CWE-639"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3473.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "11.6.0"
          },
          {
            "last_affected": "11.6.0"
          },
          {
            "introduced": "11.5.0"
          },
          {
            "last_affected": "11.5.3"
          },
          {
            "introduced": "11.4.0"
          },
          {
            "last_affected": "11.4.4"
          },
          {
            "introduced": "10.11.0"
          },
          {
            "last_affected": "10.11.14"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "Mattermost versions 11.6.x \u003c= 11.6.0, 11.5.x \u003c= 11.5.3, 11.4.x \u003c= 11.4.4, 10.11.x \u003c= 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",
  "id": "CVE-2026-3473",
  "modified": "2026-07-08T05:37:37.068092695Z",
  "published": "2026-05-22T10:27:02.600Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3473.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://mattermost.com/security-updates"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-3473"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Improper file ownership validation in the Boards API allows unauthorised file access"
}