CVE-2026-74325

Technical Description

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).

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