LightFTP 2.3.1 contains a residual race condition vulnerability (an incomplete fix for CVE-2024-11144) in the worker_thread_cleanup() function of ftpserv.c that allows remote unauthenticated attackers to destabilize or crash the daemon by triggering unsynchronized access to shared per-connection state without holding the required mutex lock. Attackers can send a data-transfer command such as LIST followed immediately by ABOR to exploit the missing synchronization on shared context and detached thread id reuse, resulting in daemon destabilization or crash which can lead to a denial of service. The 2.3.1 patch only narrowed the timing window (an extra re-check and reordered cleanup), it never added the missing lock, so the underlying race remains.

LightFTP 2.3.1 contains a race condition vulnerability that allows remote attackers to crash the server by racing a fresh connection that reuses the FTP context against an in-progress ABRT cleanup. Attackers can exploit the unprotected re-check of WorkerThreadId between worker_thread_cleanup() and pthread_join() outside of MTLock to cause pthread_join() to operate on an invalid thread ID, resulting in a server crash. CVE-2024-11144 identifies an incomplete fix of this vulnerability.