CVE-2026-19541

Name of the Vulnerable Software and Affected Versions Mattermost versions 11.7.0 through 11.7.10 Mattermost versions 11.8.0 through 11.8.5 Mattermost versions 11.9.0 through 11.9.1 Mattermost versions 11.10.0 through 11.10.1

Description An issue exists where the system fails to require the re-entry of the stored client secret during the validation of an outgoing OAuth connection. This allows an authenticated user with permissions to manage outgoing OAuth connections to obtain the secret by directing the token URL to an attacker-controlled endpoint and triggering the validation process.

Recommendations Update Mattermost versions 11.7.0 through 11.7.10 to a version newer than 11.7.10. Update Mattermost versions 11.8.0 through 11.8.5 to a version newer than 11.8.5. Update Mattermost versions 11.9.0 through 11.9.1 to a version newer than 11.9.1. Update Mattermost versions 11.10.0 through 11.10.1 to a version newer than 11.10.1.