CVE-2025-37828 is a vulnerability identified in the Linux kernel specifically affecting the SCSI UFS (Universal Flash Storage) multi-queue (MCQ) subsystem. The issue arises from a race condition between the MCQ completion path and the abort handler. When a request completes, the function __blk_mq_free_request() sets the request's mq_hctx pointer to NULL. Subsequently, the ufshcd_mcq_abort() function calls ufshcd_mcq_req_to_hwq() which can return a NULL pointer if the hardware queue (hwq) has already been freed or is no longer valid. If this NULL pointer is dereferenced, it leads to a kernel crash, effectively causing a denial of service. The fix involves adding a NULL check for the hwq pointer in ufshcd_mcq_abort(). If hwq is NULL, the kernel logs an error and returns a failure code, preventing the NULL-pointer dereference and crash. This vulnerability is similar to a previously fixed race condition in the UFS core abort handling. It was discovered using the static analysis tool KNighter. The vulnerability affects certain Linux kernel versions identified by specific commit hashes. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet.

For European organizations relying on Linux-based systems, especially those using devices with UFS storage and multi-queue SCSI subsystems (common in embedded systems, mobile devices, and some server environments), this vulnerability could lead to system instability or denial of service due to kernel crashes. Such crashes could disrupt critical services, data processing, or operational continuity. While the vulnerability does not appear to allow privilege escalation or data leakage directly, the denial of service impact can be significant in environments requiring high availability, such as financial institutions, healthcare providers, and industrial control systems prevalent in Europe. The lack of known exploits reduces immediate risk, but the potential for targeted attacks exploiting this race condition remains, especially in environments where attackers can induce aborts or manipulate SCSI requests. The impact is primarily on system availability and reliability.

European organizations should prioritize updating their Linux kernel to versions that include the patch addressing CVE-2025-37828. Since the fix involves a NULL pointer check in the kernel code, applying the official kernel updates or backported patches from trusted Linux distributions is essential. Organizations using custom or embedded Linux kernels should ensure their maintainers integrate this fix promptly. Additionally, system administrators should monitor kernel logs for error messages related to ufshcd_mcq_abort() to detect potential exploitation attempts or instability. Implementing strict access controls to limit who can issue SCSI commands or abort requests can reduce the risk of exploitation. For critical systems, consider deploying kernel live patching solutions to apply fixes without downtime. Finally, conduct thorough testing of updated kernels in staging environments to ensure stability before production deployment.