CVE-2024-41078 is a vulnerability identified in the Linux kernel's Btrfs filesystem quota group (qgroup) implementation. The issue arises during the process of disabling quota enforcement on a Btrfs filesystem. Specifically, if an error occurs while cleaning the quota tree or deleting the quota root from the root tree, the code prematurely jumps to an exit label without properly releasing the reference to the quota root. This results in a reference leak because the quota root pointer (fs_info->quota_root) is set to NULL before these cleanup steps, leaving the quota root object unreleased and thus leaking kernel memory. The root cause is a missing call to btrfs_put_root() in the error handling path, which should decrement the reference count and free the quota root when no longer needed. This bug has existed since the introduction of qgroups in 2012, initially due to missing free calls on the quota root and related nodes before roots were reference counted. The fix involves ensuring that btrfs_put_root() is always called on the quota root during the error exit path to prevent the leak. While the vulnerability does not directly enable code execution or privilege escalation, the memory leak can degrade system stability over time, especially on systems heavily utilizing Btrfs quotas. The affected versions are specific Linux kernel commits identified by their hashes, indicating that this is a low-level kernel bug affecting systems running these kernel versions with Btrfs and quota groups enabled. No known exploits are reported in the wild as of the publication date, and no CVSS score has been assigned yet.

For European organizations, the impact of CVE-2024-41078 primarily concerns systems running Linux kernels with Btrfs filesystems and quota groups enabled. Such systems could experience gradual memory leaks leading to resource exhaustion, potentially causing system instability, degraded performance, or crashes. This is particularly relevant for data centers, cloud providers, and enterprises relying on Linux servers for storage-intensive applications using Btrfs quotas for managing disk usage. While the vulnerability does not directly compromise confidentiality or integrity, availability could be affected if the leak leads to kernel memory exhaustion and system downtime. Organizations with large-scale deployments of Linux servers using Btrfs quotas, such as hosting providers or research institutions with extensive storage needs, may face operational disruptions if unpatched. However, since exploitation requires quota disable operations and the leak is a resource leak rather than a direct exploit vector, the immediate risk is moderate. The absence of known exploits reduces urgency but does not eliminate the need for patching to maintain system reliability and prevent potential denial-of-service conditions over time.

European organizations should prioritize updating their Linux kernels to versions that include the patch fixing CVE-2024-41078. Specifically, kernel maintainers and system administrators should apply the patch that ensures btrfs_put_root() is called in all error paths during quota disable operations. In environments where immediate patching is not feasible, administrators should monitor systems for unusual memory usage patterns or kernel resource leaks related to Btrfs quota operations. Avoid disabling quotas frequently or in automated scripts until patched. Additionally, organizations should audit their use of Btrfs quota groups to confirm whether this feature is enabled and assess the exposure. Employing kernel live patching solutions where available can reduce downtime associated with applying fixes. Regular system health checks and kernel logs monitoring can help detect early signs of memory leaks. Finally, maintain good backup and recovery procedures to mitigate potential availability impacts from system instability.