{"id":"CVE-2026-15754","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-15754","generatedAt":"2026-10-28T09:26:23.746Z","title":"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…","description":"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","published":"2026-08-17T15:16:54.000Z","lastModified":"2026-08-18T20:24:59.000Z","status":"Analyzed","sourceIdentifier":"responsibledisclosure@mattermost.com","cvss":{"version":"3.1","score":4.2,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:H/A:N"},"cwe":["CWE-863"],"affected":["mattermost/mattermost server"],"epss":{"score":0.00246,"percentile":0.15747,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.25%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://mattermost.com/security-updates","tags":["Vendor Advisory"],"source":"responsibledisclosure@mattermost.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-15754","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}