CVE-2025-12421
published 2025-11-27CVE-2025-12421: 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…
PriorityP266critical9.9CVSS 3.1
AVNACLPRLUINSCCHIHAH
EPSS
0.32%
23.8th percentile
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
13 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| github.com | mattermost_mattermost-server | >= 10.11.0 < 10.11.5 | 10.11.5 |
| github.com | mattermost_mattermost-server | >= 10.12.0 < 10.12.2 | 10.12.2 |
| github.com | mattermost_mattermost-server | >= 10.5.0 < 10.5.13 | 10.5.13 |
| github.com | mattermost_mattermost-server | >= 11.0.0 < 11.0.3 | 11.0.3 |
| github.com | mattermost_mattermost_server_v8 | >= 0 < 8.0.0-20251022210333-acda1fb5dd46 | 8.0.0-20251022210333-acda1fb5dd46 |
| mattermost | mattermost | 10.11.0 – 10.11.4 | — |
| mattermost | mattermost | 10.12.0 – 10.12.1 | — |
| mattermost | mattermost | 10.5.0 – 10.5.12 | — |
| mattermost | mattermost | 11.0.0 – 11.0.2 | — |
| mattermost | mattermost_server | >= 10.11.0 < 10.11.5 | 10.11.5 |
| mattermost | mattermost_server | >= 10.12.0 < 10.12.2 | 10.12.2 |
| mattermost | mattermost_server | >= 10.5.0 < 10.5.13 | 10.5.13 |
| mattermost | mattermost_server | >= 11.0.0 < 11.0.3 | 11.0.3 |
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OSV
Mattermost fails to to verify the token used during code exchange in github.com/mattermost/mattermost-server
osv·2025-12-15
CVE-2025-12421 Mattermost fails to to verify the token used during code exchange in github.com/mattermost/mattermost-server
Mattermost fails to to verify the token used during code exchange in github.com/mattermost/mattermost-server
Mattermost fails to to verify the token used during code exchange in github.com/mattermost/mattermost-server.
NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.
(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)
The additional affected modules and versions are: github.com/mattermost/mattermost-server from v10.5.0 before v10.5.13, from v10.11.0 before v10.11.5, from v10.12.0 before v10.12.2, from v11.0.0 before v11.0.3.
GHSA
Mattermost fails to to verify the token used during code exchange
ghsa·2025-11-27
CVE-2025-12421 [CRITICAL] CWE-287 Mattermost fails to to verify the token used during code exchange
Mattermost fails to to verify the token used during code exchange
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).
OSV
Mattermost fails to to verify the token used during code exchange
osv·2025-11-27
CVE-2025-12421 [CRITICAL] Mattermost fails to to verify the token used during code exchange
Mattermost fails to to verify the token used during code exchange
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).
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2025-11-27
Published