{"id":"CVE-2025-12421","state":"PUBLISHED","title":"Account Takeover via Code Exchange Endpoint","description":"Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to to verify that the token used during the code exchange originates from the same authentication flow, which allows an authenticated user to perform account takeover via a specially crafted email address used when switching authentication methods and sending a request to the /users/login/sso/code-exchange endpoint. The vulnerability requires ExperimentalEnableAuthenticationTransfer to be enabled (default: enabled) and RequireEmailVerification to be disabled (default: disabled).","publishedAt":"2025-11-27T17:47:04.944Z","updatedAt":"2026-02-26T16:07:25.754Z","severity":{"score":9.9,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","source":"Mattermost"},"assigner":"Mattermost","products":["Mattermost Mattermost"],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"11.0.0","status":"affected","lessThanOrEqual":"11.0.2","versionType":"semver"},{"version":"10.12.0","status":"affected","lessThanOrEqual":"10.12.1","versionType":"semver"},{"version":"10.11.0","status":"affected","lessThanOrEqual":"10.11.4","versionType":"semver"},{"version":"10.5.0","status":"affected","lessThanOrEqual":"10.5.12","versionType":"semver"},{"version":"11.1.0","status":"unaffected"},{"version":"11.0.3","status":"unaffected"},{"version":"10.12.2","status":"unaffected"},{"version":"10.11.5","status":"unaffected"},{"version":"10.5.13","status":"unaffected"}]}],"references":["https://mattermost.com/security-updates"],"weaknesses":["CWE-303"],"ingestedAt":"2026-10-29T20:08:31.050Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/12xxx/CVE-2025-12421.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-12421","state":"PUBLISHED","datePublished":"2025-11-27T17:47:04.944Z","dateUpdated":"2026-02-26T16:07:25.754Z","assignerShortName":"Mattermost","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateReserved":"2025-10-28T16:54:12.491Z"},"containers":{"cna":{"title":"Account Takeover via Code Exchange Endpoint","descriptions":[{"lang":"en","value":"Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to to verify that the token used during the code exchange originates from the same authentication flow, which allows an authenticated user to perform account takeover via a specially crafted email address used when switching authentication methods and sending a request to the /users/login/sso/code-exchange endpoint. The vulnerability requires ExperimentalEnableAuthenticationTransfer to be enabled (default: enabled) and RequireEmailVerification to be disabled (default: disabled)."}],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"11.0.0","status":"affected","lessThanOrEqual":"11.0.2","versionType":"semver"},{"version":"10.12.0","status":"affected","lessThanOrEqual":"10.12.1","versionType":"semver"},{"version":"10.11.0","status":"affected","lessThanOrEqual":"10.11.4","versionType":"semver"},{"version":"10.5.0","status":"affected","lessThanOrEqual":"10.5.12","versionType":"semver"},{"version":"11.1.0","status":"unaffected"},{"version":"11.0.3","status":"unaffected"},{"version":"10.12.2","status":"unaffected"},{"version":"10.11.5","status":"unaffected"},{"version":"10.5.13","status":"unaffected"}]}],"references":[{"url":"https://mattermost.com/security-updates"}],"metrics":[{"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","baseSeverity":"CRITICAL","baseScore":9.9},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-303","lang":"en","type":"CWE","description":"CWE-303: Incorrect Implementation of Authentication Algorithm"}]}],"providerMetadata":{"shortName":"Mattermost","orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateUpdated":"2025-11-27T17:47:04.944Z"},"credits":[{"lang":"en","type":"finder","value":"daw10"}],"solutions":[{"value":"Update Mattermost to versions 11.1.0, 11.0.3, 10.12.2, 10.11.5, 10.5.13 or higher.","lang":"en"}],"source":{"advisory":"MMSA-2025-00544","defect":["https://mattermost.atlassian.net/browse/MM-66299"],"discovery":"EXTERNAL"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2025-12421","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2025-12-02T04:55:57.705451Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-02-26T16:07:25.754Z"}}]}}}