CVE-2026-68409: wifi: mac80211: defer link RX stats percpu free to RCU
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: defer link RX stats percpu free to RCU
staremovelink() frees a removed MLO link's RX stats percpu buffer right away, but defers only the link container to RCU:
stainfofreelink(&alloc->info); kfreercu(alloc, rcuhead);
The RX fast path reads linksta under rcureadlock and writes the percpu stats. A reader that resolved linksta before the removal keeps the pointer. The container stays alive from the kfreercu, so the read still works. But the percpu block it points to is already freed. This needs usesrss. That is when pcpurxstats exists.
The full STA teardown frees the deflink stats only after synchronizenet(). 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.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-68409?
The severity of CVE-2026-68409 is rated at risk 24.
How do I fix CVE-2026-68409?
To fix CVE-2026-68409, update your Linux kernel to the latest version where the vulnerability has been resolved.
What systems are affected by CVE-2026-68409?
CVE-2026-68409 affects the Linux kernel's mac80211 component within the wifi subsystem.
What is the impact of CVE-2026-68409?
The impact of CVE-2026-68409 can lead to improper handling of link RX stats per-cpu buffers, potentially affecting network performance.
When was CVE-2026-68409 published?
CVE-2026-68409 was published on August 10, 2026.