CVE-2026-28736

{"id": "CVE-2026-28736", "cveTags": [{"tags": ["unsupported-when-assigned"], "sourceIdentifier": "responsibledisclosure@mattermost.com"}], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "responsibledisclosure@mattermost.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 4.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "LOW"}, "impactScore": 1.4, "exploitabilityScore": 2.8}]}, "published": "2026-04-03T14:16:29.517", "references": [{"url": "https://github.com/mattermost-community/focalboard", "tags": ["Product"], "source": "responsibledisclosure@mattermost.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "responsibledisclosure@mattermost.com", "description": [{"lang": "en", "value": "CWE-639"}]}], "descriptions": [{"lang": "en", "value": "** 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."}], "lastModified": "2026-04-28T00:19:54.037", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:mattermost:focalboard:8.0.0:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "42087E46-C9CC-46D7-B424-55537457FE0A"}], "operator": "OR"}]}], "sourceIdentifier": "responsibledisclosure@mattermost.com"}