data/osv/GO-2026-5256.json

{
  "schema_version": "1.3.1",
  "id": "GO-2026-5256",
  "modified": "0001-01-01T00:00:00Z",
  "published": "0001-01-01T00:00:00Z",
  "aliases": [
    "CVE-2026-28759",
    "GHSA-8h9w-w78c-vvr3"
  ],
  "summary": "Mattermost does not verify remote cluster channel access when processing shared channel membership removals in github.com/mattermost/mattermost-server",
  "details": "Mattermost does not verify remote cluster channel access when processing shared channel membership removals in github.com/mattermost/mattermost-server.\n\nNOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.\n\n(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)\n\nThe additional affected modules and versions are: github.com/mattermost/mattermost-server/v5 before v5.3.2-0.20260216150504-8738f8c4b3d4.",
  "affected": [
    {
      "package": {
        "name": "github.com/mattermost/mattermost-server",
        "ecosystem": "Go"
      },
      "ranges": [
        {
          "type": "SEMVER",
          "events": [
            {
              "introduced": "10.11.0+incompatible"
            },
            {
              "fixed": "10.11.14+incompatible"
            },
            {
              "introduced": "11.4.0+incompatible"
            },
            {
              "fixed": "11.4.4+incompatible"
            },
            {
              "introduced": "11.5.0+incompatible"
            },
            {
              "fixed": "11.5.2+incompatible"
            }
          ]
        }
      ],
      "ecosystem_specific": {}
    },
    {
      "package": {
        "name": "github.com/mattermost/mattermost-server/v5",
        "ecosystem": "Go"
      },
      "ranges": [
        {
          "type": "SEMVER",
          "events": [
            {
              "introduced": "0"
            }
          ]
        }
      ],
      "ecosystem_specific": {
        "custom_ranges": [
          {
            "type": "ECOSYSTEM",
            "events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "5.3.2-0.20260216150504-8738f8c4b3d4"
              }
            ]
          }
        ]
      }
    },
    {
      "package": {
        "name": "github.com/mattermost/mattermost-server/v6",
        "ecosystem": "Go"
      },
      "ranges": [
        {
          "type": "SEMVER",
          "events": [
            {
              "introduced": "0"
            }
          ]
        }
      ],
      "ecosystem_specific": {}
    },
    {
      "package": {
        "name": "github.com/mattermost/mattermost/server/v8",
        "ecosystem": "Go"
      },
      "ranges": [
        {
          "type": "SEMVER",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.0.0-20260216150504-8738f8c4b3d4"
            }
          ]
        }
      ],
      "ecosystem_specific": {}
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-8h9w-w78c-vvr3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-28759"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/commit/8738f8c4b3d42b2b687a6231e72f313357a2e891"
    },
    {
      "type": "WEB",
      "url": "https://mattermost.com/security-updates"
    }
  ],
  "database_specific": {
    "url": "https://pkg.go.dev/vuln/GO-2026-5256",
    "review_status": "UNREVIEWED"
  }
}