CVE-2026-74407 wifi: ath11k: cancel SSR work items during PCI shutdown
A race condition in the ath11k WiFi driver during PCI shutdown can cause a kernel crash via NULL pointer dereference.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74407?
CVE-2026-74407 is a high-severity vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath11k: cancel SSR work items during PCI shutdown
A reboot can crash the kernel if it overlaps with WLAN firmware crash recovery (SSR). The crash is a NULL pointer dereference in the MHI teardown path while freeing DMA-backed MHI contexts.
Simplified trace: dma_free_attrs mhi_deinit_dev_ctxt [mhi] ath11k_pci_power_down [ath11k_pci] ath11k_pci_shutdown [ath11k_pci] device_shutdown kernel_restart
On the host side, SSR is driven by the MHI RDDM callback, which queues reset_work to perform device recovery. reset_work power-cycles the device by calling ath11k_hif_power_down() followed by ath11k_hif_power_up(). The power-down phase deinitializes MHI and frees DMA resources.
Shutdown/reboot runs fully asynchronously with this RDDM-driven SSR recovery flow. As a result, the shutdown path (ath11k_pci_shutdown() -> ath11k_pci_power_down()) can race with the SSR recovery sequence.
Fix this by canceling SSR-related work items during PCI shutdown, marking the device as unregistering, and serializing the RDDM callback path that checks and queues reset_work. This ensures that no new SSR recovery work can be queued once teardown has started, and that any in-flight recovery work is fully synchronized before device power-down, preventing MHI teardown and DMA resource freeing from running more than once.
Note: This issue only affects PCI/MHI-based devices. AHB-based ath11k devices do not queue reset_work in normal SSR flows.
Tested-on: WCN6855 hw2.1 PCI WLAN.HSP.1.1-04866.5-QCAHSPSWPL_V1_V2_SILICONZ_IOE-1
Which versions are affected by CVE-2026-74407?
How do I fix CVE-2026-74407?
Apply the vendor's patch.
Is CVE-2026-74407 being exploited?
There is no known exploitation of CVE-2026-74407 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74407, DEBIAN-CVE-2026-74407, GHSA-r6wh-wch9-fxjr, UBUNTU-CVE-2026-74407.