{"id":"CVE-2026-82920","state":"PUBLISHED","title":"Mattermost ABAC parent policy bypass via policy update endpoint","description":"Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7 fail to enforce authorization boundaries on the access control policy update endpoint which allows a channel or team administrator to detach a system-assigned ABAC parent policy via a crafted PUT /api/v4/access_control_policies request with an empty imports list.. Mattermost Advisory ID: MMSA-2026-00724","publishedAt":"2026-09-14T13:59:01.993Z","updatedAt":"2026-09-14T19:23:01.097Z","severity":{"score":5.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N","source":"Mattermost"},"assigner":"Mattermost","products":["Mattermost Mattermost"],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"11.9.0","status":"affected","lessThanOrEqual":"11.9.0","versionType":"semver"},{"version":"11.8.0","status":"affected","lessThanOrEqual":"11.8.4","versionType":"semver"},{"version":"11.7.0","status":"affected","lessThanOrEqual":"11.7.7","versionType":"semver"},{"version":"11.10.0","status":"unaffected"},{"version":"11.9.1","status":"unaffected"},{"version":"11.8.5","status":"unaffected"},{"version":"11.7.8","status":"unaffected"}]}],"references":["https://mattermost.com/security-updates"],"weaknesses":["CWE-863"],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/82xxx/CVE-2026-82920.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-82920","state":"PUBLISHED","datePublished":"2026-09-14T13:59:01.993Z","dateUpdated":"2026-09-14T19:23:01.097Z","assignerShortName":"Mattermost","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateReserved":"2026-08-31T11:19:09.113Z"},"containers":{"cna":{"title":"Mattermost ABAC parent policy bypass via policy update endpoint","descriptions":[{"lang":"en","value":"Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7 fail to enforce authorization boundaries on the access control policy update endpoint which allows a channel or team administrator to detach a system-assigned ABAC parent policy via a crafted PUT /api/v4/access_control_policies request with an empty imports list.. Mattermost Advisory ID: MMSA-2026-00724"}],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"11.9.0","status":"affected","lessThanOrEqual":"11.9.0","versionType":"semver"},{"version":"11.8.0","status":"affected","lessThanOrEqual":"11.8.4","versionType":"semver"},{"version":"11.7.0","status":"affected","lessThanOrEqual":"11.7.7","versionType":"semver"},{"version":"11.10.0","status":"unaffected"},{"version":"11.9.1","status":"unaffected"},{"version":"11.8.5","status":"unaffected"},{"version":"11.7.8","status":"unaffected"}]}],"references":[{"url":"https://mattermost.com/security-updates","name":"MMSA-2026-00724","tags":["vendor-advisory"]}],"metrics":[{"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"NONE","version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N","baseSeverity":"MEDIUM","baseScore":5.5},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-863","lang":"en","type":"CWE","description":"CWE-863: Incorrect Authorization"}]}],"providerMetadata":{"shortName":"Mattermost","orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateUpdated":"2026-09-14T13:59:01.993Z"},"credits":[{"lang":"en","type":"finder","value":"kiwi_71"}],"solutions":[{"value":"Update Mattermost to versions 11.10.0, 11.9.1, 11.8.5, 11.7.8 or higher.","lang":"en"}],"source":{"advisory":"MMSA-2026-00724","defect":["https://mattermost.atlassian.net/browse/MM-69781"],"discovery":"EXTERNAL"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-82920","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-09-14T19:13:28.324125Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-14T19:23:01.097Z"}}]}}}