Description
Postiz is an AI social media scheduling tool. In versions prior to 2.21.8, the Skool integration callback signed an attacker-controlled JSON blob into a session-shape JWT using the application's JWT_SECRET, and the auth middleware trusted every claim in that JWT without re-resolving the user from the database. Any authenticated Postiz user could forge a SUPERADMIN session and impersonate arbitrary organizations. This allowed Full Access to the following: all parts of Postiz, including users registered to the specific instance and the ability to post in the name of the victim's social media channels added to that Postiz instance. This issue has been fixed in version 2.21.8.
Problem types
CWE-302: Authentication Bypass by Assumed-Immutable Data
CWE-345: Insufficient Verification of Data Authenticity
CWE-863: Incorrect Authorization
Product status
References
github.com/...iz-app/security/advisories/GHSA-j77w-h625-56q2
github.com/...ommit/23696d2973510ae1f3f48bfa41a6bfbbf9827b05
gadvisory.org/advisories/PSA-2026-2CAQ96
github.com/gitroomhq/postiz-app/releases/tag/v2.21.8