A NULL pointer dereference exists in the `ath11k spectral scan config()` function within the `drivers/net/wireless/ath/ath11k/spectral.c` module of the Linux kernel. This issue occurs when `ath11k` modules are removed using `rmmod` while spectral scan is enabled, leading to a system crash and potential denial of service. The crash is triggered in the `ath11k spectral process data()` function during the spectral deinitialization process.