{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-15754","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","state":"PUBLISHED","assignerShortName":"Mattermost","dateReserved":"2026-07-14T16:02:49.735Z","datePublished":"2026-08-17T14:36:56.282Z","dateUpdated":"2026-08-17T15:25:38.145Z"},"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Mattermost","vendor":"Mattermost","versions":[{"lessThanOrEqual":"11.7.6","status":"affected","version":"11.7.0","versionType":"semver"},{"lessThanOrEqual":"11.8.3","status":"affected","version":"11.8.0","versionType":"semver"},{"version":"11.9.0","status":"unaffected"},{"version":"11.7.7","status":"unaffected"},{"version":"11.8.4","status":"unaffected"}]}],"credits":[{"lang":"en","type":"finder","value":"KennySki"}],"descriptions":[{"lang":"en","value":"Mattermost versions 11.7.x <= 11.7.6, 11.8.x <= 11.8.3 The access control policy unassign endpoint fails to re-validate that each target channel still belongs to the requesting admin's team, which allows an authenticated team administrator to remove ABAC (attribute-based access control) policy assignments from channels outside their team via the policy unassign API after a channel has been moved to another team.. Mattermost Advisory ID: MMSA-2026-00718"}],"metrics":[{"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"HIGH","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"NONE","version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:H/A:N","baseSeverity":"MEDIUM","baseScore":4.2},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"lang":"en","type":"CWE","description":"CWE-863: Incorrect Authorization","cweId":"CWE-863"}]}],"references":[{"url":"https://mattermost.com/security-updates","name":"MMSA-2026-00718","tags":["vendor-advisory"]}],"solutions":[{"value":"Update Mattermost to versions 11.9.0, 11.7.7, 11.8.4 or higher.","lang":"en"}],"source":{"advisory":"MMSA-2026-00718","defect":["https://mattermost.atlassian.net/browse/MM-69800"],"discovery":"EXTERNAL"},"title":"Missing per-channel team-scope check in ABAC access control policy unassign allows cross-team policy removal","providerMetadata":{"orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","shortName":"Mattermost","dateUpdated":"2026-08-17T14:36:56.282Z"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-17T14:50:36.703223Z","id":"CVE-2026-15754","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-08-17T15:25:38.145Z"}}]}}