{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "11.7.0"
              },
              {
                "fixed": "11.7.8"
              },
              {
                "introduced": "11.8.0"
              },
              {
                "fixed": "11.8.5"
              },
              {
                "introduced": "11.9.0"
              },
              {
                "fixed": "11.9.1"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "a9e574a82633915f22071f0d7ca2b006f249ec2a"
            },
            {
              "fixed": "d42004bb3046de3ed176938a34b1a70c1c3d9421"
            },
            {
              "introduced": "e8bd2b8a871cbeff6943bead62328478118188df"
            },
            {
              "fixed": "d9c17e42b19c27dfac0ebe6840d954a41e626890"
            },
            {
              "introduced": "583461af10fc9b2aef2871c722fc4376db695832"
            },
            {
              "fixed": "1f738d345805168964a55e5860aac9c747dceb78"
            }
          ],
          "repo": "https://github.com/mattermost/mattermost",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Mattermost",
    "cwe_ids": [
      "CWE-863"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82920.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "11.8.0"
          },
          {
            "last_affected": "11.8.4"
          },
          {
            "introduced": "11.7.0"
          },
          {
            "last_affected": "11.7.7"
          },
          {
            "introduced": "11.9.0"
          },
          {
            "last_affected": "11.9.0"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "Mattermost versions 11.9.x \u003c= 11.9.0, 11.8.x \u003c= 11.8.4, 11.7.x \u003c= 11.7.7 fail to enforce authorization boundaries on the access control policy update endpoint which allows a channel or team administrator to detach a system-assigned ABAC parent policy via a crafted PUT /api/v4/access_control_policies request with an empty imports list.. Mattermost Advisory ID: MMSA-2026-00724",
  "id": "CVE-2026-82920",
  "modified": "2026-10-09T02:30:29.179250528Z",
  "published": "2026-09-14T13:59:01.993Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82920.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://mattermost.com/security-updates"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-82920"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Mattermost ABAC parent policy bypass via policy update endpoint"
}