Mattermost versions 10.10.x <= 10.10.1, 10.5.x <= 10.5.9, 10.9.x <= 10.9.4 fail to validate the redirect_to parameter, allowing an attacker to craft a malicious link that, once a user authenticates with their SAML provider, could post the user’s cookies to an attacker-controlled URL.
Fix
Patch, vendor advisory and mitigation references on NVD 1
- https://mattermost.com/security-updates Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 5.4 · mattermostNVD modified 2026-10-19 17:10
Affected (CPE criteria) 1
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
References 1
- https://mattermost.com/security-updates Vendor Advisory