CVE-2026-31548: wifi: cfg80211: cancel pmsr_free_wk in cfg80211_pmsr_wdev_down
In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: cancel pmsrfreewk in cfg80211pmsrwdevdown
When the nl80211 socket that originated a PMSR request is closed, cfg80211releasepmsr() sets the request's nlportid to zero and schedules pmsrfreewk to process the abort asynchronously. If the interface is concurrently torn down before that work runs, cfg80211pmsrwdevdown() calls cfg80211pmsrprocessabort() directly. However, the already- scheduled pmsrfreewk work item remains pending and may run after the interface has been removed from the driver. This could cause the driver's abortpmsr callback to operate on a torn-down interface, leading to undefined behavior and potential crashes.
Cancel pmsrfreewk synchronously in cfg80211pmsrwdevdown() before calling cfg80211pmsrprocessabort(). This ensures any pending or in-progress work is drained before interface teardown proceeds, preventing the work from invoking the driver abort callback after the interface is gone.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.113-1Fixed in 7.2.12-1Fixed in 7.2.13-1 - Upgrade
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ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1064.72+fips1 - Compensating control
In cfg80211_pmsr_wdev_down(), cancel pmsr_free_wk synchronously before calling cfg80211_pmsr_process_abort(), ensuring pending or in-progress work is drained before interface teardown.
Event History
Frequently Asked Questions
What conditions are required to trigger this issue?
A PMSR request must have been created through an nl80211 socket, that socket must close so asynchronous abort work is scheduled, and the associated wireless interface must be torn down before the queued work runs. Exploitation requires local access with low privileges and does not require user interaction.
Which systems are realistically exposed?
Systems using the Linux kernel wireless cfg80211/nl80211 stack and a driver implementing the PMSR abort callback are relevant. The failure occurs during concurrent PMSR request cleanup and wireless-interface teardown.
What is the impact if the race occurs?
Pending asynchronous work can invoke the driver's abort_pmsr callback after the interface has been removed. This can result in undefined behavior and potential kernel crashes, with CVSS indicating high impacts to confidentiality, integrity, and availability.
What does the fix change?
The fix synchronously cancels and drains pmsr_free_wk in cfg80211_pmsr_wdev_down() before processing the PMSR abort and proceeding with interface teardown. This prevents pending or in-progress abort work from operating on a torn-down interface.