{"schema_version":"1.9.0","id":"CVE-2025-12421","published":"2025-11-27T17:47:04.944Z","modified":"2026-08-12T03:51:15.180956585Z","aliases":["GHSA-mp6x-97xj-9x62","GO-2025-4170"],"related":["SUSE-SU-2026:0037-1","openSUSE-SU-2026:21483-1"],"summary":"Account Takeover via Code Exchange Endpoint","details":"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":[{"ranges":[{"type":"GIT","repo":"https://github.com/mattermost/mattermost","events":[{"introduced":"58bd34fd34cbd7d3da777d627b6cffdf8a532930"},{"fixed":"288281e8cbf15260ad074b883a263b796cdb3e28"},{"introduced":"5b955468ea1ea8b56c0fb10feb258a36a767d7bb"},{"fixed":"46b5c436bb3093cc1da3fa2455f93d4c52389eee"},{"introduced":"ba3dc1612ce8f37bf9814b1ea6364181fb5abd62"},{"fixed":"364c2203de00fe0d8424b6b46d6f0eeb02a2539a"},{"introduced":"0"},{"fixed":"feb598ed2b7ac3cb78a253b032ad7e4628b0de00"}],"database_specific":{"cpe":"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"10.5.0"},{"fixed":"10.5.13"},{"introduced":"10.11.0"},{"fixed":"10.11.5"},{"introduced":"10.12.0"},{"fixed":"10.12.2"},{"introduced":"11.0.0"},{"fixed":"11.0.3"}],"source":"CPE_RANGE"}}],"versions":["v11.0.3-rc1","v10.12.1","v10.11.4-rc3","v10.11.4","v10.5.12","v11.0.2","v10.11.4-rc2","v11.0.1-rc3","v11.0.1","v10.5.12-rc1","v10.11.4-rc1","v10.12.1-rc1","v11.0.1-rc2","v11.0.1-rc1","v11.0.0-alpha.1","v10.11.3","server/public/v0.1.19","v10.5.11","server/public/v0.1.18","v10.12.0","mattermost-redux@10.12.0","@mattermost/types@10.12.0","@mattermost/client@10.12.0","server/public/v0.1.17","v10.11.2-rc2","v10.11.2","v10.5.11-rc1","v10.11.2-rc1","v10.5.10","v10.11.1","v10.5.10-rc2","v10.11.1-rc1","v10.11.0-rc3","v10.11.0","mattermost-redux@10.11.0","@mattermost/types@10.11.0","@mattermost/client@10.11.0","v10.5.10-rc1","server/public/v0.1.16","v10.5.9","v10.5.9-rc4","v10.5.9-rc3","v10.5.9-rc2","preview-v0.1","v10.5.9-rc1","v10.5.8","server/public/v0.1.15","v10.5.8-rc1","server/public/v0.1.14","v10.5.7","v10.5.6-rc1","v10.5.6","server/public/v0.1.13","v10.5.5","server/public/v0.1.12","v10.5.5-rc1","v10.5.4-rc2","v10.5.4","v10.5.4-rc1","v10.5.3","v10.5.3-rc1","server/public/v0.1.11","v10.5.2","v10.5.1","v10.5.1-rc2","v10.5.1-rc1","v10.5.0-rc6","v10.5.0","@mattermost/types@10.5.0","@mattermost/client@10.5.0","server/public/v0.1.10","server/public/v0.1.9","server/public/v0.1.8","server/public/v0.1.7","server/public/v0.1.6","server/public/v0.1.5","server/public/v0.1.4","server/public/v0.1.3","server/public/v0.1.2","server/public/v0.1.1","server/public/v0.1.0","server/public/v0.0.18","server/public/v0.0.17","server/public/v0.0.16","server/public/v0.0.15","server/public/v0.0.14","server/public/v0.0.13","server/public/v0.0.12","server/public/v0.0.11","server/public/v0.0.10","server/public/v0.0.9","server/public/v0.0.8","server/public/v0.0.7","server/public/v0.0.6","server/public/v0.0.5","cloud-2022-11-24-1","cloud-2022-11-11-1","cloud-2022-10-06-1","cloud-2022-09-08-1","cloud-2022-08-10-1","cloud-2022-07-20-1","v5.2.0-rc2","v5.2.0-rc1","v5.1.0-rc1","v5.0.0-rc1","v4.10.0-rc1","v4.9.0-rc1","v4.8.0-rc1","v4.7.0-rc1","v4.6.0-rc2","v4.6.0-rc1","v4.5.0-rc1","v4.4.0-rc1","v4.3.0-rc1","v4.2.0-rc1","v0.5.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-12421.json"}}],"references":[{"type":"WEB","url":"https://mattermost.com/security-updates"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/12xxx/CVE-2025-12421.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-12421"}],"database_specific":{"cna_assigner":"Mattermost","cwe_ids":["CWE-303"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/12xxx/CVE-2025-12421.json","unresolved_ranges":[{"extracted_events":[{"introduced":"11.0.0"},{"last_affected":"11.0.2"},{"introduced":"10.12.0"},{"last_affected":"10.12.1"},{"introduced":"10.11.0"},{"last_affected":"10.11.4"},{"introduced":"10.5.0"},{"last_affected":"10.5.12"}],"source":"AFFECTED_FIELD"}]},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"}]}