CVE-2023-52493 is a vulnerability identified in the Linux kernel specifically related to the MHI (Modem Host Interface) bus host driver. The issue arises from improper lock management in the channel buffer queuing process. In the vulnerable code path, the Linux kernel takes both read and write locks on the channel in succession without properly releasing the read lock before queuing buffers. This improper locking sequence can lead to multiple locks being held simultaneously, which may cause a soft lockup—a state where the kernel becomes unresponsive due to deadlock or livelock conditions. The vulnerability is addressed by dropping the read lock in the parse_xfer_event() function before invoking client callbacks that queue buffers and acquire the write lock. This change ensures that buffer queuing operations occur without holding the channel read lock, preventing the lock contention and potential kernel soft lockup. The vulnerability does not appear to have any known exploits in the wild as of the published date, and no CVSS score has been assigned yet. The affected versions are identified by specific kernel commit hashes, indicating that the issue is present in certain recent Linux kernel builds prior to the fix. This vulnerability primarily affects systems running Linux kernels that include the MHI bus host driver, which is commonly used in embedded systems and devices that interface with modems or similar hardware components. The fix involves careful synchronization and lock management to maintain kernel stability and prevent denial of service conditions caused by kernel hangs.

For European organizations, the impact of CVE-2023-52493 can be significant, especially for those relying on Linux-based embedded systems, telecommunications infrastructure, or network devices that utilize the MHI bus host driver. A kernel soft lockup can lead to system hangs or crashes, resulting in denial of service (DoS) conditions. This can disrupt critical services, particularly in sectors such as telecommunications, industrial control systems, and IoT deployments where Linux is prevalent. The vulnerability does not directly expose confidentiality or integrity risks but can severely affect availability. Organizations operating Linux servers, network appliances, or embedded devices with vulnerable kernel versions may experience unexpected downtime, impacting business continuity and operational reliability. Given the widespread use of Linux in European data centers, telecom networks, and industrial environments, unpatched systems could face stability issues, leading to service interruptions and increased operational costs. Although no active exploitation is reported, the potential for accidental or targeted triggering of the soft lockup exists, especially in environments where the MHI bus host driver is actively used.

To mitigate CVE-2023-52493, European organizations should prioritize updating their Linux kernel to the latest stable version that includes the fix for this vulnerability. Specifically, kernel versions incorporating the patch that drops the read lock before queuing buffers in the MHI bus host driver should be deployed. For embedded and specialized devices, vendors should be contacted to obtain updated firmware or kernel patches. Additionally, organizations should audit their systems to identify devices and servers running affected kernel versions with the MHI bus host driver enabled. Where immediate patching is not feasible, implementing monitoring for kernel soft lockups and system hangs can provide early warning signs of exploitation or triggering of this vulnerability. System administrators should also review kernel lock usage and consider isolating vulnerable systems from critical networks to reduce impact. Finally, maintaining robust backup and recovery procedures will help minimize downtime in case of system crashes caused by this issue.