{"id":"CVE-2026-28736","sourceIdentifier":"responsibledisclosure@mattermost.com","published":"2026-04-03T14:16:29.517","lastModified":"2026-10-23T22:10:00.160","vulnStatus":"Analyzed","cveTags":[{"sourceIdentifier":"responsibledisclosure@mattermost.com","tags":["unsupported-when-assigned"]}],"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."},{"lang":"es","value":"NO COMPATIBLE CUANDO ASIGNADO  La versión 8.0 de Focalboard no valida la propiedad de los archivos al servir archivos subidos. Esto permite a un atacante autenticado que conoce el ID de archivo de una víctima leer el contenido del archivo. NOTA: Focalboard como producto independiente no recibe mantenimiento y no se emitirá ninguna corrección."}],"affected":[{"source":"responsibledisclosure@mattermost.com","affectedData":[{"vendor":"Mattermost","product":"Focalboard","defaultStatus":"unaffected","versions":[{"version":"0","lessThanOrEqual":"8.0","versionType":"semver","status":"affected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"responsibledisclosure@mattermost.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","baseScore":4.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"NONE"},"exploitabilityScore":2.8,"impactScore":1.4}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-04-03T14:53:54.422014Z","id":"CVE-2026-28736","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"responsibledisclosure@mattermost.com","type":"Secondary","description":[{"lang":"en","value":"CWE-639"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:mattermost:focalboard:8.0.0:*:*:*:*:*:*:*","matchCriteriaId":"42087E46-C9CC-46D7-B424-55537457FE0A"}]}]}],"references":[{"url":"https://github.com/mattermost-community/focalboard","source":"responsibledisclosure@mattermost.com","tags":["Product"]}]}