CVE-2025-38013

In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211: Set nchannels after allocating struct cfg80211scan_request

Make sure that nchannels is set after allocating the struct cfg80211registereddevice::intscan_req member. Seen with syzkaller:

UBSAN: array-index-out-of-bounds in net/mac80211/scan.c:1208:5 index 0 is out of range for type 'struct ieee80211channel *[] _countedby(nchannels)' (aka 'struct ieee80211_channel *[]')

This was missed in the initial conversions because I failed to locate the allocation likely due to the "sizeof(void *)" not matching the "channels" array type.