CVE-2026-98334: wifi: mac80211: reset state when starting AP fails

CVE-2026-98334: wifi: mac80211: reset state when starting AP fails

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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

wifi: mac80211: reset state when starting AP fails

ieee80211_start_ap() can set enable_beacon (and beacon_int) and fail
later, leaving it set forever. Scanning can then attempt to restore
beaconing on such an interface, leading to:

  Oops: divide error: 0000 [#1] SMP KASAN NOPTI
  RIP: 0010:mac80211_hwsim_link_info_changed+0xca7/0xf00
  Call Trace:
   drv_link_info_changed+0x413/0x860 net/mac80211/driver-ops.c:495
   ieee80211_link_info_change_notify+0x24b/0x3c0 net/mac80211/main.c:427
   ieee80211_offchannel_return+0x381/0x580 net/mac80211/offchannel.c:160
   __ieee80211_scan_completed+0x993/0xe30 net/mac80211/scan.c:519
   ieee80211_scan_work+0x472/0x2010 net/mac80211/scan.c:1193
   cfg80211_wiphy_work+0x2b7/0x550 net/wireless/core.c:538

in hwsim. Also, cfg80211 then allows changing the interface type,
and the off-channel path getgs confused about beaconing as well,
leading to another warning:

  WARNING: net/mac80211/driver-ops.c:468 at drv_link_info_changed+0x583/0x880
   ieee80211_link_info_change_notify+0x24b/0x3c0 net/mac80211/main.c:427
   ieee80211_offchannel_stop_vifs+0x328/0x5c0 net/mac80211/offchannel.c:122
   ieee80211_start_sw_scan net/mac80211/scan.c:583 [inline]
   __ieee80211_start_scan+0xfb6/0x1af0 net/mac80211/scan.c:882

Reset the state on failures to always have it correct.

The Linux kernel CVE team has assigned CVE-2026-98334 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 3.9 with commit d6a83228823fc0cc8d79d95c9f0bf568b7317862 and fixed in 6.12.112 with commit d83da43e9b3b3b1bad99ac5a1065f1c63ad5fc32
	Issue introduced in 3.9 with commit d6a83228823fc0cc8d79d95c9f0bf568b7317862 and fixed in 6.18.54 with commit 5d5ff5b36f5748a2a077f875a73ccb26860d3fcc
	Issue introduced in 3.9 with commit d6a83228823fc0cc8d79d95c9f0bf568b7317862 and fixed in 7.2.8 with commit 6eac225f59c1c2277ac74f8a716d6df0ba3b8d28
	Issue introduced in 3.9 with commit d6a83228823fc0cc8d79d95c9f0bf568b7317862 and fixed in 7.3-rc4 with commit 3f28551d0241254a75626d868041c6340285088b

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-98334
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/mac80211/cfg.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/d83da43e9b3b3b1bad99ac5a1065f1c63ad5fc32
	https://git.kernel.org/stable/c/5d5ff5b36f5748a2a077f875a73ccb26860d3fcc
	https://git.kernel.org/stable/c/6eac225f59c1c2277ac74f8a716d6df0ba3b8d28
	https://git.kernel.org/stable/c/3f28551d0241254a75626d868041c6340285088b