CVE-2026-68408
Received Received - Intake

Deadlock in Linux Kernel WiFi Subsystem

Publication date: 2026-08-10

Last updated on: 2026-08-10

Assigner: kernel.org

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().

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Meta Information

Published
2026-08-10
Last Modified
2026-08-10
Generated
2026-08-10
AI Q&A
2026-08-10
EPSS Evaluated
N/A
NVD
CVE-2026-68408
EUVD
EUVD-2026-55594

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a deadlock vulnerability in the Linux kernel's wifi configuration subsystem. It occurs when a network interface is torn down while a PMSR (Per-STA Multi-link Probe Request) session is being processed. The deadlock happens because two operations try to acquire the same lock simultaneously: one waiting to cancel a work item and another trying to execute it.

Detection Guidance

This vulnerability is specific to the Linux kernel's wifi subsystem and involves a deadlock scenario during interface teardown. Detection requires checking kernel logs for deadlock warnings or hangs during wireless interface operations. No direct commands detect this vulnerability, but monitoring for system hangs or kernel warnings during wifi operations may indicate the issue.

Impact Analysis

This vulnerability could cause system hangs or crashes when network interfaces are being shut down, particularly during high-load scenarios or when managing wireless connections. It may lead to denial of service conditions where the system becomes unresponsive.

Mitigation Strategies

Apply the kernel patch that converts pmsr_free_wk to wiphy_work to resolve the deadlock. Update to a kernel version containing the fix. If immediate patching is not possible, avoid closing netlink sockets owning PMSR sessions while interfaces are tearing down to reduce exposure.

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