{"id":"CVE-2026-28736","aliases":["GHSA-vph7-r229-qxpf","GO-2026-5670"],"url":"https://o3.security/vulnerability/CVE-2026-28736","summary":"Focalboard IDOR in file content endpoint allows cross-user file access (unsupported product, no fix)","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.","published":"2026-04-03T13:25:53.399Z","modified":"2026-07-31T18:30:12.731623155Z","cvss":{"score":4.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"},"epss":{"score":0.00221,"percentile":0.12679,"asOf":"2026-08-08"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/mattermost/focalboard","fixedVersion":null}],"fix":null,"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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-31T18:30:12.731623155Z"}}