CVE-2022-49771 is a vulnerability identified in the Linux kernel's device-mapper (dm) ioctl interface, specifically related to the handling of the list_versions operation. The vulnerability arises from a race condition between two calls to dm_target_iterate, which are used to estimate and then fill a buffer with version information about device-mapper targets. The first call estimates the required buffer size while holding a read lock, but between this call and the second call (which fills the buffer), no lock is held. This gap allows for the possibility that target modules may be loaded concurrently, increasing the required buffer size beyond the initial estimate. The code attempts to handle this overflow scenario, but incorrectly sets the buffer boundaries, leading to a situation where the second call may write more data than the size indicated by param->data_size. Consequently, the ioctl interface copies only up to param->data_size into userspace, truncating part of the result and potentially causing inconsistent or incomplete data to be returned. The fix involves correctly setting the buffer end pointer to the initially estimated needed size and handling buffer overflow by signaling userspace to allocate a larger buffer and retry. Additionally, a bug in the size estimation function list_version_get_needed was corrected to properly account for string lengths. This vulnerability affects Linux kernel versions identified by the commit hash 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and was published on May 1, 2025. There are no known exploits in the wild at this time, and no CVSS score has been assigned yet.

For European organizations, the impact of CVE-2022-49771 depends on the deployment of Linux systems utilizing the device-mapper functionality, which is common in enterprise environments for managing logical volumes and storage virtualization. The vulnerability could lead to inconsistent or truncated data being returned via the ioctl interface, potentially causing misbehavior in applications or services relying on accurate device-mapper version information. While this may not directly lead to privilege escalation or remote code execution, it could be exploited to cause denial of service or data integrity issues in storage management operations. Systems performing dynamic module loading during these operations are particularly at risk. Given the widespread use of Linux in European data centers, cloud infrastructures, and critical systems, any disruption in storage management could affect availability and reliability of services. However, the lack of known exploits and the requirement for local interaction with the ioctl interface reduce the immediate threat level. Organizations with automated or scripted storage management tools that depend on this interface may experience operational issues or require updates to handle the corrected behavior.

European organizations should prioritize updating their Linux kernel versions to include the patch that fixes CVE-2022-49771. Since the vulnerability arises from a race condition during module loading and ioctl calls, applying the official kernel update is the most effective mitigation. Additionally, organizations should audit and monitor systems that perform dynamic module loading and device-mapper operations to detect unusual behavior or errors related to storage management. Limiting access to the ioctl interface to trusted users and processes can reduce the risk of exploitation. Implementing strict controls on who can load kernel modules and perform device-mapper operations will further mitigate potential abuse. For environments where immediate patching is not feasible, consider restricting or disabling unnecessary device-mapper ioctl operations temporarily. Finally, ensure that storage management tools and scripts are tested against updated kernel versions to handle any changes in ioctl behavior gracefully.