CVE-2024-50202 is a vulnerability identified in the Linux kernel's nilfs2 filesystem implementation. The issue arises from improper error handling in the function nilfs_find_entry(), which is responsible for searching directory entries within nilfs2 filesystems. Specifically, when nilfs_get_folio() fails to load a directory page or folio due to corruption or other errors, nilfs_find_entry() currently ignores these errors instead of propagating them. This can lead to a task hang in vcs_open() during fuzz testing, as reported by Syzbot. The root cause is that if the filesystem image is corrupted and the directory inode size is large, nilfs_check_folio() may repeatedly emit error messages, especially if the directory page is zero-filled or fails sanity checks. The vulnerability stems from an outdated interface that does not allow nilfs_find_entry() and its callers to propagate error codes such as -EIO (input/output error) and -ENOMEM (out of memory). The fix involves modifying nilfs_find_entry() and its callers to properly propagate these error codes, preventing hangs and excessive error logging. This vulnerability affects Linux kernel versions identified by the commit hash 2ba466d74ed74f073257f86e61519cb8f8f46184 and potentially other versions using the nilfs2 filesystem code with the described behavior. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations, the impact of CVE-2024-50202 depends largely on the usage of the nilfs2 filesystem within their Linux environments. Nilfs2 is a log-structured filesystem designed for continuous snapshotting and is less commonly used than ext4 or XFS but may be deployed in specialized storage systems or environments requiring high data integrity and snapshot capabilities. The vulnerability can cause system hangs or degraded performance when accessing corrupted nilfs2 directories, potentially leading to denial of service (DoS) conditions on affected systems. This can disrupt critical services, especially in data centers or infrastructure relying on Linux servers with nilfs2 volumes. While the vulnerability does not appear to allow privilege escalation or remote code execution, the denial of service impact could affect availability of services, data access, and system stability. European organizations with storage systems, backup solutions, or specialized Linux deployments using nilfs2 should be aware of this risk. Given the lack of known exploits, the immediate threat level is moderate, but unpatched systems remain vulnerable to stability issues and potential operational disruptions.

European organizations should take the following specific mitigation steps: 1) Identify Linux systems using the nilfs2 filesystem by auditing storage configurations and mount points. 2) Apply the latest Linux kernel patches that address CVE-2024-50202 as soon as they become available from trusted Linux distributions or kernel maintainers. 3) If immediate patching is not possible, monitor system logs for repeated nilfs_check_folio() error messages or task hangs related to vcs_open(), which may indicate exploitation or triggering of this vulnerability. 4) Implement filesystem integrity checks and regular backups to detect and recover from nilfs2 filesystem corruption that could trigger this issue. 5) Consider isolating or limiting access to systems using nilfs2 to reduce exposure. 6) Engage with Linux distribution vendors for backported patches and security advisories relevant to your environment. 7) Incorporate this vulnerability into vulnerability management and incident response plans to ensure timely detection and remediation.