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

wifi: cfg80211: ibss: ref BSS entry for joined event

When the IBSS is joined, we only record the BSSID/channel in the event
and look up the BSS entry when processing it. However, that's racy,
e.g. a new scan with NL80211_SCAN_FLAG_FLUSH can remove it, causing a
warning in the event work:

  !bss
  WARNING: net/wireless/ibss.c:37 at __cfg80211_ibss_joined+0x3d3/0x440
  Workqueue: cfg80211 cfg80211_event_work
   cfg80211_process_wdev_events+0x39f/0x5b0 net/wireless/util.c:1144
   cfg80211_process_rdev_events+0xa1/0x110 net/wireless/util.c:1179
   cfg80211_event_work+0x2f/0x40 net/wireless/core.c:393

Do the lookup early (the driver is expected to only join an IBSS that
has a BSS entry) and keep a reference to it.