CVE-2026-68409

Technical Description

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

wifi: mac80211: defer link RX stats percpu free to RCU

sta_remove_link() frees a removed MLO link's RX stats percpu buffer right

away, but defers only the link container to RCU:

sta_info_free_link(&alloc->info);

kfree_rcu(alloc, rcu_head);

The RX fast path reads link_sta under rcu_read_lock and writes the percpu

stats. A reader that resolved link_sta before the removal keeps the

pointer. The container stays alive from the kfree_rcu, so the read still

works. But the percpu block it points to is already freed. This needs

uses_rss. That is when pcpu_rx_stats exists.

The full STA teardown frees the deflink stats only after

synchronize_net(). The link removal path had no such barrier. The race is

hard to win in practice, but the free should still wait for RCU.

Free the link together with its data from a single RCU callback, so the

percpu block is reclaimed only after readers drain.

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