Permission Bypass in Playbook Run Creation

{
  "id": "7f943545ee80858d387cfb18d37688d7c22e078d8aa67f4fcfb31bef0144db5a",
  "url": "https://osv.dev/vulnerability/CVE-2026-26304",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Permission Bypass in Playbook Run Creation",
    "summary": "Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2 fail to verify run_create permission for empty playbookId, which allows team members to create unauthorized runs via the playbook run API. Mattermost Advisory ID: MMSA-2025-00542",
    "evidence": "osv:CVE-2026-26304",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-26304",
      "aliases": [
        "CVE-2026-26304",
        "GHSA-4pmx-622h-x359",
        "GO-2026-4812"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mattermost/mattermost",
              "type": "GIT",
              "events": [
                {
                  "introduced": "ab7b138824c61fe1fe815243d7e2a914dec49c8b"
                },
                {
                  "fixed": "005521aa79666e6960bc3302f6172b810f6bff3a"
                },
                {
                  "introduced": "d27a2195068ddfa3ce17cf470f9739e4edb94b83"
                },
                {
                  "fixed": "4082c3dcf285e4d1a386d2ef37f14f39dc5a0094"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "11.2.0"
                      },
                      {
                        "fixed": "11.2.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "11.3.0"
                      },
                      {
                        "fixed": "11.3.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v11.3.1-rc1",
            "v11.2.2",
            "v11.3.0-rc4",
            "v11.3.0-rc3",
            "v11.3.0",
            "mattermost-redux@11.3.0",
            "@mattermost/types@11.3.0",
            "@mattermost/client@11.3.0",
            "v11.2.1",
            "v11.2.1-rc1",
            "v11.2.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-26304.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:21.822888569Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26304.json",
        "https://mattermost.com/security-updates",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-26304"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-863"
        ],
        "cna_assigner": "Mattermost",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "11.3.0"
                  },
                  {
                    "last_affected": "11.3.0"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandaloneSingleVersion"
              }
            ]
          },
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "11.2.0"
                  },
                  {
                    "last_affected": "11.2.2"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26304.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-26304",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 488271,
  "published_at": "2026-03-16T19:53:21.65+00:00"
}