Executive brief
stoatchat is a messaging platform with push notifications and mention badges. An authenticated user can crash all acknowledgement workers by sending five specially crafted role-mention messages, disabling push notifications and mention badges for all users deployment-wide until the API process is manually restarted. This is a service disruption attack requiring only user authentication.
Technical details
The vulnerability is an uncaught exception (panic) in the mass-mention processing code when a role mention is not properly cleared from Saved Notes messages. The acknowledgement worker assumes mass mentions originate from a TextChannel and panics when encountering other channel types. Five workers consume the same queue without supervision, so five crafted messages terminate the entire worker pool. An authenticated attacker can trigger this by sending role-mention messages to their own Saved Notes channel.
Affected products
- stoatchat before 0.15.5
Timeline
- 2026-09-26: disclosed
- 2026-09-26: patched: Fixed in version 0.15.5