{"identifier":"CVE-2026-19076","cve":{"id":"CVE-2026-19076","description":"Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to reject OAuth application sessions in the account type switch endpoint, which allows an attacker with a valid OAuth bearer token for a target user to permanently take over that user's SSO-backed account by setting an attacker-controlled password and detaching the account from its identity provider via a crafted request to POST /api/v4/users/login/switch.. Mattermost Advisory ID: MMSA-2026-00758","published":"2026-10-16T08:17:13.177000+00:00","modified":"2026-10-27T20:57:34.380000+00:00","status":"Analyzed","score":4.4,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N","cvss_version":"3.1","affected":[{"criteria":"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*","versionStartIncluding":"11.7.0","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"11.7.10"},{"criteria":"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*","versionStartIncluding":"11.8.0","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"11.8.6"},{"criteria":"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*","versionStartIncluding":"11.9.0","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"11.9.2"},{"criteria":"cpe:2.3:a:mattermost:mattermost_server:11.10.0:*:*:*:*:*:*:*","versionStartIncluding":"","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":""}],"weaknesses":["CWE-863"],"references":[{"url":"https://mattermost.com/security-updates","source":"responsibledisclosure@mattermost.com","tags":["Vendor Advisory"]}],"kev":null,"kev_checked":true,"metrics":{"cvssMetricV31":[{"source":"responsibledisclosure@mattermost.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N","baseScore":4.4,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":0.7,"impactScore":3.6},{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N","baseScore":4.9,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":1.2,"impactScore":3.6}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-10-16T14:06:08.450522Z","id":"CVE-2026-19076","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*","versionStartIncluding":"11.7.0","versionEndExcluding":"11.7.10","matchCriteriaId":"0D5A7979-C6DD-4EEA-B7C4-60C425EAD2C3"},{"vulnerable":true,"criteria":"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*","versionStartIncluding":"11.8.0","versionEndExcluding":"11.8.6","matchCriteriaId":"864932C7-FD92-48AC-8789-DF73D5CA9AAF"},{"vulnerable":true,"criteria":"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*","versionStartIncluding":"11.9.0","versionEndExcluding":"11.9.2","matchCriteriaId":"2F937268-2154-4B45-B9E0-8B3451070CD0"},{"vulnerable":true,"criteria":"cpe:2.3:a:mattermost:mattermost_server:11.10.0:*:*:*:*:*:*:*","matchCriteriaId":"C945CD83-FCEB-439D-8F18-02213CE7E7BF"}]}]}],"source":"nvd","retrieved_at":"2026-10-28T10:26:10.630977+00:00","exploited":false,"kev_stale":false,"products":["mattermost / mattermost server"],"priority":{"label":"Assess exposure and vendor guidance","reasons":["No higher-priority signal is available in the current stored evidence."]},"epss":{"probability":0.00199,"percentile":0.0966,"date":"2026-10-28","stale":false},"version_assessment":null},"news":[],"campaigns":[],"domains":[{"domain":"mattermost.com","source_url":"https://mattermost.com/security-updates","investigate_url":"https://investigate.aeglixmind.com/#mattermost.com"}],"arsenal_url":"https://arsenal.aeglixmind.com/?cve=CVE-2026-19076","catalog_url":"https://cves.aeglixmind.com/cve/CVE-2026-19076","research_url":"https://investigate.aeglixmind.com/research/cve/CVE-2026-19076","coverage":{"news_candidates_checked":0,"campaign_candidates_checked":0,"bounded":false,"notice":"Exact CVE mentions in stored public excerpts and reviewed campaign content only. A mention is not proof of exploitation, attribution or tool suitability. Missing matches do not establish absence."}}