CVE-2024-26758 is a medium-severity vulnerability in the Linux kernel's md (multiple device) subsystem, which manages software RAID arrays. The issue arises from improper handling of suspended RAID arrays during recovery operations. Specifically, the function md_check_recovery() incorrectly ignores the suspended state of an array, leading to a situation where the sync_thread responsible for synchronizing RAID data cannot be properly unregistered. This occurs because mddev_suspend() does not stop the sync_thread, and md_check_recovery() returns early if the array is suspended, preventing the clearing of the MD_RECOVERY_RUNNING flag. Consequently, the system can hang during RAID stop operations, as the sync_thread remains stuck waiting on recovery flags that never clear. The problem is not limited to device-mapper RAID (dm-raid) but affects the md subsystem more broadly. The root cause is a race condition and improper state management in the recovery synchronization logic. The vulnerability was introduced after commit f52f5c71f3d4 and can be triggered by specific test scripts such as shell/integrity-caching.sh. The fix involves modifying md_check_recovery() to ignore the suspended state, allowing proper cleanup of the sync_thread, and follow-up patches aim to improve dm-raid handling by freezing the sync_thread during suspend operations. The CVSS v3.1 score is 5.5 (medium), with an attack vector of local access, low complexity, requiring low privileges, no user interaction, and impacting availability only (no confidentiality or integrity impact). No known exploits are reported in the wild at this time.

For European organizations relying on Linux servers with software RAID configurations managed by the md subsystem, this vulnerability can lead to system hangs during RAID array suspension and stopping operations. This can cause temporary denial of service, impacting availability of critical storage systems, potentially disrupting business operations, data processing, and services dependent on RAID arrays. While the vulnerability does not compromise data confidentiality or integrity, the availability impact can be significant in environments where RAID arrays are frequently suspended or stopped for maintenance or failover. Organizations running local Linux servers with RAID arrays, especially in data centers, cloud infrastructure, or enterprise storage solutions, are at risk. The requirement for local access and low privileges means that attackers or malicious insiders with limited system access could trigger the hang, increasing the risk in multi-user or shared environments. The absence of known exploits reduces immediate risk, but the medium severity and potential for denial of service warrant timely patching to maintain operational stability.

European organizations should promptly apply the official Linux kernel patches that address CVE-2024-26758 once available from their Linux distribution vendors. Until patches are applied, administrators should avoid suspending or stopping RAID arrays managed by the md subsystem on production systems, especially during critical operational periods. Monitoring system logs for unusual hangs or sync_thread activity can help detect attempts to trigger the issue. For environments using dm-raid, follow-up patches improving sync_thread freezing during suspend should also be applied to enhance stability. Additionally, organizations should restrict local access to trusted users only, enforce strict privilege controls, and audit user activities to reduce the risk of exploitation. Testing patches in staging environments before deployment is recommended to ensure compatibility and stability. Finally, maintaining up-to-date backups and RAID health monitoring can mitigate the impact of any unexpected availability issues.