CVE-2026-64570wifi: mac80211: fix fils_discovery double free on alloc failure

Official description

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: fix fils_discovery double free on alloc failure ieee80211_set_fils_discovery() calls kfree_rcu() on the old template before allocating the replacement. If the kzalloc() then fails, it returns -ENOMEM while link->u.ap.fils_discovery still points at the object already queued for freeing. A later update or AP teardown (ieee80211_stop_ap()) re-queues that same rcu_head; the second free is caught by KASAN when the RCU sheaf is processed in softirq: BUG: KASAN: double-free in rcu_free_sheaf (mm/slub.c:5850) Free of addr ffff88800c065280 by task swapper/0/0 ... __rcu_free_sheaf_prepare (mm/slub.c:2634 mm/slub.c:2940) rcu_free_sheaf (mm/slub.c:5850) rcu_core (kernel/rcu/tree.c:2617 kernel/rcu/tree.c:2869) handle_softirqs (kernel/softirq.c:622) The buggy address belongs to the cache kmalloc-96 of size 96 Queue the old object for kfree_rcu() only after the new one is published, matching ieee80211_set_probe_resp() and ieee80211_set_s1g_short_beacon().

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/e2c55079155a953db669ca1986a985fa286bad95
• https://git.kernel.org/stable/c/5baaa1042f71dd4b8e418f2cdd516808702d229b
• https://git.kernel.org/stable/c/1981fba71797ec95e6755fb882cad88899a2a84f
• https://git.kernel.org/stable/c/286e52a799fa158bdbd77da1426c4d93f9a6e7ad