A NULL pointer dereference vulnerability has been reported to affect several QNAP operating system versions. If exploited, the vulnerability could allow authenticated administrators to launch a denial-of-service (DoS) attack via a network. QES is not affected. We have already fixed the vulnerability in the following versions: QuTS hero h5.0.1.2515 build 20230907 and later QuTS hero h5.1.0.2453 build 20230708 and later QuTS hero h4.5.4.2476 build 20230728 and later QuTScloud c5.1.0.2498 and later QTS 5.1.0.2444 build 20230629 and later QTS 4.5.4.2467 build 20230718 and later