Linux Kernel NULL Pointer Dereference Vulnerability in nl80211 Off-Channel Check

A vulnerability in the Linux kernel's handling of off-channel checks in the nl80211 Wi-Fi management interface has been addressed. The issue involved a NULL pointer dereference that could occur in Access Point (AP) mode when a link was established by userspace but not yet activated. In this scenario, the channel definition (chandef) was present but invalid, lacking a valid channel. The vulnerability has been resolved by implementing a check to ignore such links with invalid chandefs.

Impact

Exploitation of this vulnerability could lead to a NULL pointer dereference, causing a crash or undefined behavior in the kernel.