{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:mattermost:focalboard:8.0.0:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "last_affected": "8.0"
              },
              {
                "introduced": "8.0.0"
              },
              {
                "last_affected": "8.0.0"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "CPE_STRING"
            ]
          },
          "events": [
            {
              "introduced": "568a5f01b6b9c15f84b8733b60d7a88c222939c2"
            },
            {
              "last_affected": "568a5f01b6b9c15f84b8733b60d7a88c222939c2"
            }
          ],
          "repo": "https://github.com/mattermost-community/focalboard",
          "type": "GIT"
        }
      ],
      "versions": [
        "8.0.0"
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Mattermost",
    "cwe_ids": [
      "CWE-639"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28736.json"
  },
  "details": "** UNSUPPORTED WHEN ASSIGNED ** Focalboard version 8.0 fails to validate file ownership when serving uploaded files. This allows an authenticated attacker who knows a victim's fileID to read the content of the file. NOTE: Focalboard as a standalone product is not maintained and no fix will be issued.",
  "id": "CVE-2026-28736",
  "modified": "2026-08-12T03:51:47.387555357Z",
  "published": "2026-04-03T13:25:53.399Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28736.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-28736"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mattermost-community/focalboard"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Focalboard IDOR in file content endpoint allows cross-user file access (unsupported product, no fix)"
}