Nezha Dashboard from 1.8.0 before 2.3.13 contains an improper locking vulnerability where a non-deferred mutex unlock leaks on a nil-map panic path. Any authenticated non-admin member can issue four notification API calls to permanently deadlock the alerting subsystem, then exhaust memory with blocking requests.
The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.
Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.