CVE-2022-49914 is a vulnerability identified in the Linux kernel's Btrfs filesystem implementation, specifically within the function resolve_indirect_refs() that handles back reference walking. The issue arises when an error occurs during backref walking: the code jumps to an 'out' label and calls ulist_free() on the 'parents' ulist. While ulist_free() correctly frees the elements in the ulist, it does not free any inode lists attached to those elements via the 'aux' field of the ulist nodes. This results in a memory leak of inode lists. The vulnerability was addressed by replacing the call to ulist_free() with free_leaf_list(), a function that properly frees both the ulist elements and any attached inode lists. The fix involved moving the static function free_leaf_list() to a higher scope and simplifying it by removing unnecessary code. This vulnerability is related to resource management and memory leaks within the Btrfs filesystem code path in the Linux kernel. Although it does not directly cause corruption or code execution, leaking inode lists could lead to increased memory consumption and potential denial of service (DoS) conditions if exploited repeatedly or under heavy filesystem operations. The vulnerability affects Linux kernel versions identified by the commit hash 3301958b7c1dae8f0f5ded63aa881e0b71e78464 and presumably earlier versions before the patch. 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-2022-49914 primarily revolves around potential denial of service scenarios due to memory leaks in systems using the Btrfs filesystem on Linux. Organizations relying on Linux servers with Btrfs for critical storage—such as cloud providers, hosting companies, and enterprises running containerized workloads—may experience degraded performance or system instability if the vulnerability is triggered repeatedly. While the vulnerability does not directly lead to privilege escalation or remote code execution, the memory leak could be exploited by an attacker with local access or by malicious software to exhaust system resources, causing service interruptions. This could impact availability of services, especially in environments with high filesystem activity or where Btrfs is heavily utilized. Given the widespread use of Linux in European data centers, cloud infrastructures, and enterprise environments, the vulnerability poses a moderate operational risk. However, the lack of known exploits and the requirement for local triggering reduce the immediate threat level. Organizations with compliance requirements around system stability and uptime should prioritize patching to mitigate any risk of service disruption.

To mitigate CVE-2022-49914, European organizations should: 1) Apply the latest Linux kernel patches that include the fix for this vulnerability as soon as they become available from their Linux distribution vendors. 2) Monitor systems using Btrfs for unusual memory consumption patterns or system logs indicating filesystem errors that could be related to inode list leaks. 3) Limit local access to critical Linux systems to trusted users only, reducing the risk of exploitation by malicious insiders or compromised accounts. 4) Consider implementing resource limits (e.g., cgroups) to contain the impact of potential memory leaks on system stability. 5) For environments where Btrfs is not essential, evaluate the feasibility of using alternative, more mature filesystems (e.g., ext4 or XFS) until patches are applied. 6) Maintain robust backup and recovery procedures to minimize downtime in case of system instability. 7) Stay informed through vendor advisories and security mailing lists for any updates or emerging exploit information related to this vulnerability.