CVE-2026-68414 Overview
CVE-2026-68414 is a use-after-free vulnerability in the Linux kernel's cfg80211 wireless configuration subsystem. The flaw resides in the scheduled scan results handling path, where cfg80211_sched_scan_results() can queue rdev->sched_scan_res_wk after a driver result notification. During wiphy_unregister(), the kernel drains other rdev work items but does not drain sched_scan_res_wk. A queued or running work item can therefore cross the unregister/free boundary and access freed rdev state, triggering a use-after-free condition confirmed by KASAN reports.
Critical Impact
An attacker on an adjacent wireless network can trigger memory corruption in the Linux kernel, potentially leading to denial of service or kernel privilege escalation.
Affected Products
- Linux kernel versions containing the cfg80211 scheduled scan results work handler prior to the fix
- Wireless subsystems relying on cfg80211 sched-scan driver notifications
- Distributions shipping vulnerable kernels until backported patches are applied
Discovery Timeline
- 2026-08-10 - CVE-2026-68414 published to NVD
- 2026-08-13 - Last updated in NVD database
Technical Details for CVE-2026-68414
Vulnerability Analysis
The vulnerability is a classic use-after-free race between the wireless scheduled-scan results worker and the wiphy unregister path. cfg80211_sched_scan_results() queues rdev->sched_scan_res_wk on the cfg80211_wq when a driver reports new scheduled-scan results. The work callback then recovers the containing cfg80211_registered_device, acquires the wiphy lock, and walks the scheduled-scan request list.
On the teardown path, wiphy_unregister() marks the wiphy unreachable and drains most rdev work items before cfg80211_dev_free() releases the object. However, sched_scan_res_wk was not included in that drain. A queued result notification can therefore execute after cfg80211_dev_free() frees the rdev, producing kernel reads and writes against freed memory.
Root Cause
The root cause is missing synchronization in the wiphy unregister sequence. The teardown code relied on the assumption that interface teardown would remove all pending scheduled-scan requests, but a driver notification arriving concurrently could still queue the results work item after that removal. Without a cancel_work_sync() call for sched_scan_res_wk, the object lifetime of rdev is not correctly bounded by the lifetime of its work items.
Attack Vector
Exploitation requires an attacker within wireless range capable of influencing scheduled-scan result notifications delivered by the wireless driver. The attacker must race a scan-result event against interface teardown or module unload. Success yields a read or write against freed rdev state, which KASAN reports as use-after-free in cfg80211_sched_scan_results_wk. High attack complexity reflects the narrow race window between the queued worker and cfg80211_dev_free().
The upstream fix adds cancel_work_sync() for sched_scan_res_wk in wiphy_unregister(). This removes any pending result notification and waits for a running callback to complete before cfg80211_dev_free() can release the device. See the Kernel Fix Commit 308ffdf for the authoritative patch.
Detection Methods for CVE-2026-68414
Indicators of Compromise
- KASAN reports containing use-after-free in cfg80211_sched_scan_results_wk in kernel logs
- Unexpected kernel oops or panic traces referencing cfg80211_sched_scan_results_wk+0x4a6/0x530
- Workqueue stack traces attributing faults to Workqueue: cfg80211 cfg80211_sched_scan_results_wk
- Kernel crashes correlated in time with wireless interface teardown or driver module unload
Detection Strategies
- Enable KASAN on test kernels to surface use-after-free conditions in the cfg80211 path during QA
- Collect and centralize dmesg and /var/log/kern.log output to search for the signature stack trace
- Correlate wireless interface down or rmmod events with subsequent kernel exceptions
Monitoring Recommendations
- Forward kernel logs to a central SIEM or data lake and alert on KASAN, BUG:, and cfg80211 co-occurrences
- Monitor endpoint kernel versions against distribution advisories to identify hosts still exposed
- Track wireless driver module load and unload events on Linux endpoints, especially laptops and IoT devices
How to Mitigate CVE-2026-68414
Immediate Actions Required
- Apply the upstream Linux kernel patches referenced in the stable tree and reboot affected systems
- Inventory Linux hosts using cfg80211-based wireless drivers and prioritize those exposed to untrusted wireless networks
- Subscribe to distribution security channels for backported fixes and deploy them via the standard patch pipeline
Patch Information
The fix cancels sched_scan_res_wk in wiphy_unregister() alongside the other rdev work items. cancel_work_sync() removes any pending result notification and blocks until an in-flight callback finishes, guaranteeing that cfg80211_dev_free() cannot free rdev while the work item is active. Upstream commits addressing this issue include 308ffdf, 3368457, 9293574, b119c70, and edf0730b.
Workarounds
- Disable scheduled scan (sched_scan) functionality on affected hosts where operationally feasible
- Restrict use of untrusted wireless networks on unpatched systems to reduce adjacent-network exposure
- Avoid unloading or reloading wireless driver modules while scheduled scans are active
# Verify kernel version and confirm patch presence via distribution advisory
uname -r
# Example: check for the fix commit hash in the running kernel source tree
git log --oneline | grep -E "308ffdf|3368457|9293574|b119c70|edf0730b"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
