CVE-2026-74325

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

wifi: mt76: use kfree_rcu for offchannel link in mt76_put_vif_phy_link

mt76_put_vif_phy_link() frees the offchannel mlink with plain kfree()

after rcu_assign_pointer(NULL). However, rcu_assign_pointer only prevents

future RCU readers from obtaining the pointer -- it does not wait for

existing readers that already hold it via rcu_dereference.

The TX datapath (e.g. mt7996_mac_write_txwi) dereferences mlink->wcid

and mlink->idx under rcu_read_lock. If a TX softirq obtained the pointer

via rcu_dereference just before the NULL assignment, it will dereference

freed memory after the kfree.

struct mt76_vif_link already contains an rcu_head field that is unused at

this free site -- a developer oversight, since the adjacent

kfree_rcu_mightsleep call for rx_sc in the same function shows the

pattern was understood.

Replace kfree(mlink) with kfree_rcu(mlink, rcu_head).