{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "versions": [
              {
                "introduced": "9.11.0"
              },
              {
                "fixed": "9.11.18"
              },
              {
                "introduced": "10.5.0"
              },
              {
                "fixed": "10.5.9"
              }
            ]
          },
          "events": [
            {
              "introduced": "0bc2ddd42375a75ab14e63f038165150d4f07659"
            },
            {
              "fixed": "11c36f4d1e44c36a85aa682becaa7519f63761cf"
            },
            {
              "introduced": "58bd34fd34cbd7d3da777d627b6cffdf8a532930"
            },
            {
              "fixed": "c602a4a78e1f60b9a97ee5bce509ecad4177340c"
            }
          ],
          "repo": "https://github.com/mattermost/mattermost-server",
          "type": "GIT"
        }
      ]
    }
  ],
  "details": "Mattermost versions 10.5.x \u003c= 10.5.8, 9.11.x \u003c= 9.11.17 fail to properly validate authorization for team scheme role modifications which allows Team Admins to demote Team Members to Guests via the PUT /api/v4/teams/team-id/members/user-id/schemeRoles API endpoint.",
  "id": "CVE-2025-53971",
  "modified": "2026-03-10T21:50:36.065042624Z",
  "published": "2025-08-21T08:15:30.540Z",
  "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"
    }
  ]
}