{"id":"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.","aliases":["GHSA-vph7-r229-qxpf","GO-2026-5670"],"modified":"2026-08-12T03:51:47.387555357Z","published":"2026-04-03T13:25:53.399Z","related":["openSUSE-SU-2026:21483-1"],"database_specific":{"cwe_ids":["CWE-639"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28736.json","cna_assigner":"Mattermost"},"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"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mattermost-community/focalboard","events":[{"introduced":"568a5f01b6b9c15f84b8733b60d7a88c222939c2"},{"last_affected":"568a5f01b6b9c15f84b8733b60d7a88c222939c2"}],"database_specific":{"source":["AFFECTED_FIELD","CPE_STRING"],"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"}]}}],"versions":["8.0.0","v8.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-28736.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"}]}