Unauthorized Private-to-Public Channel Conversion

{
  "id": "c6e1706b8e7f49f69d6c8e7b71976a5520a956c6a9a4479a69011db668b3d6a4",
  "url": "https://osv.dev/vulnerability/CVE-2025-27933",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Unauthorized Private-to-Public Channel Conversion",
    "summary": "Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8 fail to fail to enforce channel conversion restrictions, which allows members with permission to convert public channels to private ones to also convert private ones to public",
    "evidence": "osv:CVE-2025-27933",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2025-27933",
      "aliases": [
        "BIT-mattermost-2025-27933",
        "CVE-2025-27933",
        "GHSA-h5v9-xw2g-7hrq",
        "GO-2025-3556"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mattermost/mattermost",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0bc2ddd42375a75ab14e63f038165150d4f07659"
                },
                {
                  "fixed": "07bb4f96ed7400080f2ded5e910a947b8e6c168f"
                },
                {
                  "introduced": "14facfa730253bbf4191d3346c2fd6f282c5b446"
                },
                {
                  "fixed": "d59bc01a0225a09819692671745d61b05ee949a0"
                },
                {
                  "introduced": "7c8c0b7464fa9cd2fbfb97c65d1475b4be2e765c"
                },
                {
                  "fixed": "e644e3c8e3931a9432bbd23ff6a219c5664011e9"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "9.11.0"
                      },
                      {
                        "fixed": "9.11.9"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "10.3.0"
                      },
                      {
                        "fixed": "10.3.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "10.4.0"
                      },
                      {
                        "fixed": "10.4.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v10.4.3-rc3",
            "v10.3.4-rc3",
            "v9.11.9-rc2",
            "v10.3.4-rc2",
            "v10.4.3-rc2",
            "v10.3.4-rc1",
            "v9.11.9-rc1",
            "v10.4.3-rc1",
            "v10.3.3",
            "v9.11.8",
            "v10.4.2",
            "v10.3.2-rc2",
            "v10.3.2",
            "v9.11.7-rc3",
            "v9.11.7",
            "v10.3.2-rc1",
            "v10.4.1",
            "v9.11.7-rc2",
            "v10.4.0-rc3",
            "v10.4.0",
            "@mattermost/types@10.4.0",
            "@mattermost/client@10.4.0",
            "v9.11.7-rc1",
            "v10.3.1-rc1",
            "v10.3.1",
            "v9.11.6",
            "v10.3.0",
            "@mattermost/types@10.3.0",
            "@mattermost/client@10.3.0",
            "v9.11.6-rc2",
            "v9.11.6-rc1",
            "v9.11.5",
            "v9.11.5-rc1",
            "v9.11.4",
            "v9.11.4-rc1",
            "v9.11.3",
            "v9.11.3-rc2",
            "v9.11.3-rc1",
            "v9.11.2",
            "v9.11.2-rc2",
            "v9.11.2-rc1",
            "v9.11.1-rc1",
            "v9.11.1",
            "v9.11.0-rc3",
            "v9.11.0",
            "@mattermost/types@9.11.0",
            "@mattermost/client@9.11.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-27933.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.311978632Z",
      "provider": "osv",
      "references": [
        "https://mattermost.com/security-updates",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/27xxx/CVE-2025-27933.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-27933"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-863"
        ],
        "cna_assigner": "Mattermost",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "10.4.0"
                  },
                  {
                    "last_affected": "10.4.2"
                  },
                  {
                    "introduced": "10.3.0"
                  },
                  {
                    "last_affected": "10.3.3"
                  },
                  {
                    "introduced": "9.11.0"
                  },
                  {
                    "last_affected": "9.11.8"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/27xxx/CVE-2025-27933.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-27933",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 504836,
  "published_at": "2025-03-21T08:23:20.955+00:00"
}