CVE-2022-49543 is a vulnerability identified in the Linux kernel specifically related to the ath11k wireless driver and the MHI (Modem Host Interface) bus core subsystem. The issue arises during device recovery procedures when simulating firmware crashes on certain Qualcomm wireless chipsets (e.g., WCN6855 hw2.0). The vulnerability manifests as a warning triggered by an imbalance in device wake assertion and deassertion calls within the MHI power management transition function (mhi_pm_disable_transition). Specifically, the function mhi_deassert_dev_wake() is called without a corresponding prior call to mhi_assert_dev_wake(), due to a newly introduced check in the __mhi_device_get_sync() function that skips device wake assertion if the device is not in a normal power management state during recovery. This leads to the dev_wake flag remaining non-zero and causing kernel warnings during power management transitions. The root cause is a race or logic flaw in the power management state handling during firmware crash recovery, which results in improper synchronization of device wake states. The fix involves adding checks in the ath11k PCI read/write functions to avoid calling mhi_device_put() if mhi_device_get_sync() did not assert the device wake, thereby preventing the warning. This vulnerability is primarily a kernel warning and does not appear to cause a kernel panic or direct memory corruption. It affects Linux kernel versions containing the ath11k driver and MHI bus core, particularly on systems using Qualcomm wireless chipsets such as WCN6855 and QCA6390. The issue was identified and fixed in kernel version 5.17.0-rc3-wt-ath+ and related branches. No known exploits are reported in the wild, and the vulnerability does not have an assigned CVSS score. The vulnerability is more of a stability and logging concern during recovery scenarios rather than a direct security exploit vector.

For European organizations, the impact of CVE-2022-49543 is primarily related to system stability and reliability rather than direct security compromise. Systems running Linux kernels with affected ath11k drivers on Qualcomm wireless chipsets may experience kernel warnings during firmware crash recovery processes, which could complicate troubleshooting and potentially mask other critical issues. While no direct exploitation or privilege escalation is indicated, persistent warnings and improper power management transitions could lead to degraded wireless performance or intermittent connectivity issues in critical infrastructure or enterprise environments relying on these wireless modules. This might affect organizations using Linux-based network appliances, embedded systems, or IoT devices with Qualcomm wireless hardware. The absence of known exploits and the nature of the issue as a warning rather than a crash or data corruption reduces the immediate risk. However, organizations with high availability requirements or those performing automated recovery testing on affected hardware should be aware of this issue to avoid misinterpretation of kernel logs and to maintain system reliability.

To mitigate the effects of CVE-2022-49543, European organizations should: 1) Ensure that Linux kernel versions deployed on systems with Qualcomm ath11k wireless chipsets are updated to versions containing the fix (post 5.17.0-rc3-wt-ath+ or equivalent stable releases). 2) Validate firmware versions and driver compatibility for Qualcomm wireless modules to ensure they incorporate the corrected power management logic. 3) Monitor kernel logs for mhi_pm_disable_transition warnings and correlate them with device recovery events to distinguish this known issue from other potential faults. 4) For critical systems, implement controlled testing environments to simulate firmware crashes and verify that the warning no longer appears after patching. 5) Collaborate with hardware vendors to confirm that device firmware and drivers are aligned with kernel fixes to prevent recurrence. 6) Avoid deploying custom kernel patches or backports without thorough testing, as improper handling of MHI power states can exacerbate the issue. 7) Maintain robust incident response procedures to quickly identify and address any unexpected wireless subsystem anomalies that may arise during recovery scenarios.