CyberRota Analysis
AI-GeneratedMattermost versions 11.9.0 and earlier, as well as 11.8.4 and 11.7.7, are vulnerable due to improper validation of Dynamic Client Registration redirect URIs, allowing remote unauthenticated attackers to register OAuth clients with malicious callback hosts. This vulnerability can lead to unauthorized access and potential data exposure by bypassing the configured redirect URI allowlist. Organizations using affected Mattermost versions should prioritize patching to mitigate the risk of exploitation.
Original NVD Description
Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7 Mattermost failed to validate Dynamic Client Registration redirect URIs by URL component (matching glob patterns against the raw URI string instead) which allows a remote unauthenticated attacker to register an OAuth client with an attacker-controlled callback host that bypasses the configured redirect URI allowlist via a crafted redirect URI that places an allowlisted host/path suffix inside the query string.. Mattermost Advisory ID: MMSA-2026-00700