ZwiiCMS versions prior to 13.7.00 contain a denial-of-service vulnerability in multiple administrative endpoints due to improper authorization checks combined with flawed resource state management. When an authenticated low-privilege user requests an administrative page, the application returns 404 Not Found as expected, but incorrectly acquires and associates a temporary lock on the targeted resource with the attacker session prior to authorization. This lock prevents other users, including administrators, from accessing the affected functionality until the attacker navigates away or the session is terminated.
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.