Executive brief
Flowise, an open-source tool for building LLM applications, contains a vulnerability that allows users to change their own account passwords without knowing the current one. If an attacker manages to temporarily hijack a user's session through other means, they can use this flaw to permanently lock the original user out and maintain long-term access to the account. This undermines account security and recovery processes.
Technical details
A mass assignment vulnerability exists in the 'PUT /api/v1/user' endpoint of Flowise. The application fails to filter the request body before passing it to the service layer, where it is merged into the existing user entity using a database manager. An authenticated attacker can include a 'credential' field in the JSON request body containing a pre-computed bcrypt hash, which overwrites the stored password hash in the database. This bypasses the intended logic that requires 'oldPassword' verification. While an ID check prevents modifying other users' accounts, this flaw allows an attacker with temporary session access (e.g., via XSS or token theft) to establish persistent account control. The issue is fixed in version 3.1.2.
Affected products
- FlowiseAI flowise <= 3.1.1
Timeline
- 2026-05-14: disclosed
- 2026-05-20: advisory: GitHub Advisory published
- 2026-05-20: patched: Version 3.1.2 released
References
- https://api.github.com/users/berkdedekarginoglu
- https://github.com/berkdedekarginoglu
- https://api.github.com/users/berkdedekarginoglu/gists%7B/gist_id%7D
- https://api.github.com/users/berkdedekarginoglu/repos
- https://avatars.githubusercontent.com/u/30373481?v=4
- https://api.github.com/users/berkdedekarginoglu/events%7B/privacy%7D