CVE-2026-98340

/// Technical description

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

wifi: cfg80211: only group hidden BSSes with beacon entries

When a probe response for an unknown BSS comes in, __cfg80211_bss_update()

looks for an existing entry with the same BSSID and a hidden (zero-length

or NUL-filled) SSID, and if it finds one it groups them, using the beacon

IEs from the existing entry.

But that could find another entry without a beacon, if it was also from a

probe response (with SSID), so there's a group without beacon elements.

If a beacon with a hidden SSID for that BSSID arrives later,

cfg80211_combine_bsses() goes looking for the probe response entries that

belong to it - i.e. entries with the same BSSID and channel that have no

beacon IEs - and finds those two. They are already grouped with each

other, so it hits its

WARN_ON_ONCE(bss->pub.hidden_beacon_bss)

WARN_ON_ONCE(!list_empty(&bss->hidden_list))

which are there because an entry without beacon elements is not supposed

to be

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References