Linux Kernel mac80211 null deref in mesh_matches_local causing DoS
CVE-2026-23396 Published on March 26, 2026
wifi: mac80211: fix NULL deref in mesh_matches_local()
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: fix NULL deref in mesh_matches_local()
mesh_matches_local() unconditionally dereferences ie->mesh_config to
compare mesh configuration parameters. When called from
mesh_rx_csa_frame(), the parsed action-frame elements may not contain a
Mesh Configuration IE, leaving ie->mesh_config NULL and triggering a
kernel NULL pointer dereference.
The other two callers are already safe:
- ieee80211_mesh_rx_bcn_presp() checks !elems->mesh_config before
calling mesh_matches_local()
- mesh_plink_get_event() is only reached through
mesh_process_plink_frame(), which checks !elems->mesh_config, too
mesh_rx_csa_frame() is the only caller that passes raw parsed elements
to mesh_matches_local() without guarding mesh_config. An adjacent
attacker can exploit this by sending a crafted CSA action frame that
includes a valid Mesh ID IE but omits the Mesh Configuration IE,
crashing the kernel.
The captured crash log:
Oops: general protection fault, probably for non-canonical address ...
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
Workqueue: events_unbound cfg80211_wiphy_work
[...]
Call Trace:
<TASK>
? __pfx_mesh_matches_local (net/mac80211/mesh.c:65)
ieee80211_mesh_rx_queued_mgmt (net/mac80211/mesh.c:1686)
[...]
ieee80211_iface_work (net/mac80211/iface.c:1754 net/mac80211/iface.c:1802)
[...]
cfg80211_wiphy_work (net/wireless/core.c:426)
process_one_work (net/kernel/workqueue.c:3280)
? assign_work (net/kernel/workqueue.c:1219)
worker_thread (net/kernel/workqueue.c:3352)
? __pfx_worker_thread (net/kernel/workqueue.c:3385)
kthread (net/kernel/kthread.c:436)
[...]
ret_from_fork_asm (net/arch/x86/entry/entry_64.S:255)
</TASK>
This patch adds a NULL check for ie->mesh_config at the top of
mesh_matches_local() to return false early when the Mesh Configuration
IE is absent.
Products Associated with CVE-2026-23396
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Affected Versions
Linux:- Version 2e3c8736820bf72a8ad10721c7e31d36d4fa7790 and below c1e3f2416fb27c816ce96d747d3e784e31f4d95c is affected.
- Version 2e3c8736820bf72a8ad10721c7e31d36d4fa7790 and below 0a4da176ae4b4e075a19c00d3e269cfd5e05a813 is affected.
- Version 2e3c8736820bf72a8ad10721c7e31d36d4fa7790 and below a90279e7f7ea0b7e923a1c5ebee9a6b78b6d1004 is affected.
- Version 2e3c8736820bf72a8ad10721c7e31d36d4fa7790 and below 44699c6cdfce80a0f296b54ae9314461e3e41b3d is affected.
- Version 2e3c8736820bf72a8ad10721c7e31d36d4fa7790 and below 7c55a3deaf7eaaafa2546f8de7fed19382a0a116 is affected.
- Version 2e3c8736820bf72a8ad10721c7e31d36d4fa7790 and below c73bb9a2d33bf81f6eecaa0f474b6c6dbe9855bd is affected.
- Version 2.6.26 is affected.
- Before 2.6.26 is unaffected.
- Version 6.1.167, <= 6.1.* is unaffected.
- Version 6.6.130, <= 6.6.* is unaffected.
- Version 6.12.78, <= 6.12.* is unaffected.
- Version 6.18.20, <= 6.18.* is unaffected.
- Version 6.19.10, <= 6.19.* is unaffected.
- Version 7.0-rc5, <= * is unaffected.