MEDIUM 4.3 Go
Mattermost doesn't sanitize team member data when returned via API to users without elevated permissions
GHSA-ffpr-pfr4-g354 · CVE-2026-3636 · GO-2026-5818
Published · Modified
Description
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to sanitize team member data when returned via API to users without elevated permissions which allows a user without permissions to get data about team members roles via invoking various team API endpoints. Mattermost Advisory ID: MMSA-2026-00626.
References
Ready to move
Start Securing
Free, no credit card | First findings in minutes