CVE-2026-68408 wifi: cfg80211: convert pmsr_free_wk to wiphy_work to fix deadlock
A race condition in the Linux kernel WiFi subsystem causes a deadlock when closing PMSR sessions, leading to a local denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-68408?
CVE-2026-68408 is a vulnerability in Linux, published on 10 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: convert pmsr_free_wk to wiphy_work to fix deadlock
When a netlink socket that owns a PMSR session is closed, cfg80211_release_pmsr() clears the request's nl_portid and queues pmsr_free_wk to call cfg80211_pmsr_process_abort() asynchronously.
If the interface tears down concurrently, cfg80211_pmsr_wdev_down() is called under wiphy_lock and calls cancel_work_sync(&pmsr_free_wk) to wait for any running work. The work function acquires wiphy_lock via guard(wiphy) before calling process_abort.
This is a deadlock: wdev_down holds wiphy_lock and blocks inside cancel_work_sync(); pmsr_free_wk blocks trying to acquire that same wiphy_lock. Neither thread can proceed.
The same deadlock is reachable from cfg80211_leave_locked(), which calls cfg80211_pmsr_wdev_down() for all interface types under wiphy_lock.
Fix this by converting pmsr_free_wk from a plain work_struct to a wiphy_work. The wiphy_work dispatcher holds wiphy_lock when running work items, so the explicit guard(wiphy) in the work function is no longer needed. wiphy_work_cancel() can be called safely while holding wiphy_lock - since wiphy_lock prevents the work from running concurrently, wiphy_work_cancel() never blocks, eliminating the deadlock.
Remove the cancel_work_sync() for pmsr_free_wk from the NETDEV_GOING_DOWN handler. cfg80211_leave(), called unconditionally just before it, already cancels any pending work under wiphy_lock via wiphy_work_cancel() inside cfg80211_pmsr_wdev_down().
Which versions are affected by CVE-2026-68408?
How do I fix CVE-2026-68408?
Apply the vendor's patch.
Is CVE-2026-68408 being exploited?
There is no known exploitation of CVE-2026-68408 in the wild and no public exploit code.
Sources
Also known as AZL-95018, BELL-CVE-2026-68408, DEBIAN-CVE-2026-68408, GHSA-x755-7343-mr27, UBUNTU-CVE-2026-68408.