CVE-2024-26897

What it actually does

Race condition allows ath9k_wmi_event_tasklet to execute before device data structures are fully initialized, permitting access to uninitialized pointers during WMI event handling on USB-attached ath9k_htc devices.

Why it matters to the business

Systems using affected Linux kernels with ath9k_htc USB Wi-Fi hardware may experience unexpected crashes or loss of wireless functionality during driver load, leading to hardware downtime and requiring reboots or kernel updates.

How an attack unfolds

An attacker with local access and the specific USB Wi-Fi adapter triggers rapid device enumeration before ath9k_htc_probe_device completes, causing the tasklet to dereference uninitialized structures and crash the kernel.

How to fix it

Update to a fixed kernel version containing commit 1bc5461a21c56a36e2a7d81e152b90ce019a3905 or later stable releases (for example Linux 5.10.214 and corresponding backports). Rebuild and reboot with the patched kernel; no configuration changes are required.

How to confirm the fix worked

Confirm the running kernel contains the fix by checking git commit 1bc5461a21c56a36e2a7d81e152b90ce019a3905 or verifying the synchronization bit is set at the end of ath9k_htc_probe_device before any WMI tasklet execution.

Typical attack path

1. Attach ath9k_htc USB device to trigger early USB subsystem registration
2. Race the initialization sequence so the WMI event tasklet runs before the synchronization bit is set
3. Deliver a WMI event (other than the previously mitigated TXSTATUS) that accesses uninitialized fields
4. Trigger NULL dereference or invalid memory access resulting in kernel panic

How to detect it

Review kernel logs for ath9k or ath9k_htc NULL pointer dereference or oops messages occurring during USB device probe; correlate with device insertion events and early boot timing.

What your security team should do

• Prioritize patching kernel packages on all systems exposing ath9k_htc USB Wi-Fi hardware
• Reboot affected hosts after package installation to load the corrected driver
• Monitor vendor kernel update channels for additional backported fixes in older LTS branches