{"id":"CVE-2026-26230","state":"PUBLISHED","title":"Team Admin Privilege Escalation to Demote Members to Guest","description":"Mattermost versions 10.11.x <= 10.11.10 fail to properly validate permission requirements in the team member roles API endpoint which allows team administrators to demote members to guest role. Mattermost Advisory ID: MMSA-2025-00531","publishedAt":"2026-03-16T20:19:51.287Z","updatedAt":"2026-03-17T13:37:17.914Z","severity":{"score":3.8,"label":"Low","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N","source":"Mattermost"},"assigner":"Mattermost","products":["Mattermost Mattermost"],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"10.11.0","status":"affected","lessThanOrEqual":"10.11.10","versionType":"semver"},{"version":"11.4.0","status":"unaffected"},{"version":"10.11.11","status":"unaffected"}]}],"references":["https://mattermost.com/security-updates"],"weaknesses":["CWE-863"],"ingestedAt":"2026-10-29T20:11:21.040Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/26xxx/CVE-2026-26230.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-26230","state":"PUBLISHED","datePublished":"2026-03-16T20:19:51.287Z","dateUpdated":"2026-03-17T13:37:17.914Z","assignerShortName":"Mattermost","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateReserved":"2026-02-13T10:39:47.088Z"},"containers":{"cna":{"title":"Team Admin Privilege Escalation to Demote Members to Guest","descriptions":[{"lang":"en","value":"Mattermost versions 10.11.x <= 10.11.10 fail to properly validate permission requirements in the team member roles API endpoint which allows team administrators to demote members to guest role. Mattermost Advisory ID: MMSA-2025-00531"}],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"10.11.0","status":"affected","lessThanOrEqual":"10.11.10","versionType":"semver"},{"version":"11.4.0","status":"unaffected"},{"version":"10.11.11","status":"unaffected"}]}],"references":[{"url":"https://mattermost.com/security-updates","name":"MMSA-2025-00531","tags":["vendor-advisory"]}],"metrics":[{"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"NONE","version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N","baseSeverity":"LOW","baseScore":3.8},"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":"2026-03-16T20:19:51.287Z"},"credits":[{"lang":"en","type":"finder","value":"hackit_bharat"}],"solutions":[{"value":"Update Mattermost to versions 11.4.0, 10.11.11 or higher.","lang":"en"}],"source":{"advisory":"MMSA-2025-00531","defect":["https://mattermost.atlassian.net/browse/MM-66091"],"discovery":"EXTERNAL"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-17T13:37:10.650822Z","id":"CVE-2026-26230","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-03-17T13:37:17.914Z"}}]}}}