CVE-2022-49523 is a vulnerability identified in the Linux kernel's ath11k wireless driver module, specifically related to the handling of spectral scan functionality during module removal. The ath11k driver supports Qualcomm Atheros Wi-Fi 6 chipsets. The vulnerability manifests when the ath11k kernel module is removed (e.g., via the rmmod command) while spectral scan is enabled. Spectral scanning is a feature used for radio frequency analysis and interference detection. The issue arises because the driver does not properly disable spectral scanning before deinitializing spectral data structures, leading to a use-after-free or NULL pointer dereference in kernel space. This improper cleanup causes kernel crashes (kernel oops) with varying crash traces, as the driver attempts to access freed or invalid memory during spectral deinitialization. The provided kernel logs indicate a NULL pointer dereference at a low memory address (0x00000008) within the ath11k_spectral_process_data function, triggered during the spectral deinit sequence. The root cause is the failure to send a spectral scan disable WMI (Wireless Module Interface) command to the firmware before cleaning spectral data buffers, which leads to the driver processing stale or invalid data. This vulnerability affects Linux kernel versions containing the affected ath11k driver code, particularly those with the specified commit hash d5c65159f2895379e11ca13f62feabe93278985d. The issue was tested on Qualcomm QCN6122 hardware. While this vulnerability causes system instability and kernel crashes, there is no indication of privilege escalation or remote code execution. Exploitation requires local access to the system with the ability to unload kernel modules, which typically requires root privileges. No known exploits are reported in the wild, and no CVSS score has been assigned yet.

For European organizations, the primary impact of CVE-2022-49523 is potential denial of service (DoS) due to kernel crashes on systems using affected Linux kernels with ath11k wireless drivers. This can lead to system instability, unexpected reboots, or downtime, affecting availability of critical infrastructure, servers, or endpoints relying on Wi-Fi connectivity. Organizations deploying Linux-based systems with Qualcomm Atheros Wi-Fi 6 chipsets, especially in embedded devices, network appliances, or industrial control systems, may experience disruptions. Although the vulnerability requires local root access to trigger, an attacker who gains such access could cause repeated crashes, impacting system reliability. This could be leveraged as part of a broader attack to degrade service or disrupt operations. However, since no remote exploitation or privilege escalation is indicated, the confidentiality and integrity impact is limited. The vulnerability is more relevant for environments where wireless module management and kernel module unloading occur dynamically, such as development, testing, or specialized embedded systems. For typical enterprise Linux server deployments without ath11k hardware or module unloading, the risk is minimal.

1. Apply the official Linux kernel patches that properly disable spectral scanning before spectral deinitialization in the ath11k driver. Monitor Linux kernel updates and backport fixes if using long-term support kernels. 2. Avoid unloading the ath11k kernel module while spectral scanning is enabled. Ensure spectral scan is explicitly disabled before module removal. 3. Restrict root access and module unloading capabilities to trusted administrators only, minimizing the risk of accidental or malicious triggering of the vulnerability. 4. For embedded or specialized devices using Qualcomm Atheros Wi-Fi 6 chipsets, validate firmware and driver versions to confirm the presence of the fix. 5. Implement monitoring for kernel oops or crashes related to ath11k spectral scanning to detect potential exploitation attempts or instability. 6. Where possible, disable spectral scanning if not required for operational purposes to reduce attack surface. 7. Test kernel updates in staging environments before deployment to avoid unexpected disruptions. 8. Maintain up-to-date backups and recovery procedures to mitigate impact of potential system crashes.