{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "versions": [
              {
                "introduced": "10.11.0"
              },
              {
                "fixed": "10.11.11"
              }
            ]
          },
          "events": [
            {
              "introduced": "5b955468ea1ea8b56c0fb10feb258a36a767d7bb"
            },
            {
              "fixed": "fddd4a70bcb32eaff394a2fa5399efcd1b2ae251"
            }
          ],
          "repo": "https://github.com/mattermost/mattermost-server",
          "type": "GIT"
        }
      ]
    }
  ],
  "details": "Mattermost versions 10.11.x \u003c= 10.11.10 fail to properly validate permission requirements in the team member roles API endpoint which allows team administrators to demote members to guest role. Mattermost Advisory ID: MMSA-2025-00531",
  "id": "CVE-2026-26230",
  "modified": "2026-04-01T23:08:06.315745465Z",
  "published": "2026-03-16T21:16:33.480Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://mattermost.com/security-updates"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}