CVE-2026-68404 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: use wiphy work for socket owner autodisconnect
nl80211_netlink_notify() walks the cfg80211 wireless device list when a NETLINK_GENERIC socket is released. If the socket owns a connection, the notifier queues the embedded wdev->disconnect_wk work item.
That work is a plain work_struct today. NETDEV_GOING_DOWN cancels it, but a NETLINK_URELEASE notifier that already observed conn_owner_nlportid can queue it after that cancel returns. _cfg80211_unregister_wdev() then removes the wdev from the list and waits for RCU readers, but synchronize_net() does not drain work queued by such a reader.
Make the autodisconnect work a wiphy_work instead. The callback already needs the wiphy mutex, and wiphy_work runs under that mutex. This lets teardown cancel pending autodisconnect work while holding the mutex, without a cancel_work_sync() vs. worker locking concern.
Also cancel the wiphy work after list_del_rcu() and synchronize_net(). Any NETLINK_URELEASE notifier that had already reached the wdev list has then either queued the work and it is removed, or can no longer find the wdev.
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Analysis
by VulDB Data Team • 08/10/2026
This vulnerability exists in the linux kernel's wireless subsystem within the cfg80211 framework that manages 802.11 wireless devices. The issue stems from improper handling of work queue management during socket cleanup operations when wireless connections are terminated. The problem manifests when a NETLINK_GENERIC socket is released, triggering the nl80211_netlink_notify() function to iterate through all cfg80211 wireless devices. When a device connection is owned by the releasing socket, the notifier queues a disconnect work item through wdev->disconnect_wk which is currently implemented as a plain work_struct.
The fundamental flaw occurs in the race condition between cancellation and queuing operations during the cleanup process. Specifically when NETDEV_GOING_DOWN event occurs, it cancels the work item, but a subsequent NETLINK_URELEASE notifier that has already observed the conn_owner_nlportid can queue the work again after the cancel operation returns. This creates a scenario where the work item may be queued even after cancellation, leading to potential double execution or inconsistent state management.
The vulnerability is further exacerbated by the fact that _cfg80211_unregister_wdev() removes the wdev from the list and waits for RCU readers, but synchronize_net() does not drain work items that were queued by such readers. This means that work items that were scheduled after the cancellation but before the final cleanup can still execute, potentially causing crashes or undefined behavior. This type of vulnerability aligns with CWE-362 which describes race conditions in concurrent programming where operations may be interrupted and resumed at unexpected points.
The technical implementation involves the interaction between multiple kernel subsystems including network device management, work queue handling, and RCU (Read-Copy Update) synchronization primitives. The fix addresses this by converting the plain work_struct to a wiphy_work which is specifically designed to run under the wiphy mutex, eliminating the race condition by ensuring proper locking semantics throughout the process. This approach follows ATT&CK technique T1068 which involves exploiting weaknesses in privilege escalation and resource management.
The solution implements a more robust teardown sequence that properly cancels pending autodisconnect work while holding the mutex, eliminating the need for cancel_work_sync() versus worker locking concerns. The fix ensures that wiphy work is canceled after list_del_rcu() and synchronize_net() operations, guaranteeing that any NETLINK_URELEASE notifier that had already accessed the wdev list either successfully queued the work (which is then properly canceled) or can no longer find the device. This change provides a more reliable and predictable cleanup mechanism for wireless connections when sockets are released.
The operational impact of this vulnerability could result in system crashes, memory corruption, or inconsistent wireless connection states during socket cleanup operations. Attackers who can control network socket operations might exploit this race condition to cause denial of service or potentially escalate privileges through kernel memory corruption. The fix provides a solid foundation for maintaining wireless subsystem stability and preventing potential exploitation scenarios while maintaining the expected functionality of automatic disconnection behavior when wireless sockets are released.