Executive brief
Mastra is a TypeScript framework for building AI-powered applications and agents. When the optional mapUserToResourceId callback is not configured, authenticated users can enumerate all conversation threads and view the conversation history and metadata of other users' conversations, bypassing access controls that are intended to restrict visibility to a user's own data.
Technical details
This is an authentication bypass vulnerability in the memory API's thread ownership validation logic. The root cause is that when the mapUserToResourceId callback is omitted from configuration, the server fails to properly validate thread ownership before returning thread data. An authenticated attacker can send GET requests to /api/memory/threads to enumerate all threads in the system and access conversation history and metadata belonging to other resource owners. The vulnerability requires prior authentication but does not require user interaction. A fix is expected in versions after 1.63.0.
Affected products
- Mastra Mastra through 1.63.0
Timeline
- 2026-08-28: disclosed