CVE-2024-57892 is a high-severity use-after-free vulnerability in the Linux kernel's OCFS2 (Oracle Cluster File System version 2) implementation. The flaw occurs during the process of remounting an OCFS2 filesystem as read-only. Specifically, when the filesystem is remounted read-only, the kernel frees the dqi_priv pointer associated with quota information (sb_dqinfo(sb, type)->dqi_priv) but fails to set this pointer to NULL, leaving a dangling pointer. Subsequent operations, such as quota_getnextquota syscall, access this dangling pointer, leading to a slab-use-after-free condition. This can cause memory corruption, potentially allowing an attacker with local privileges to execute arbitrary code or cause a denial of service by crashing the kernel. The vulnerability arises because the remount operation sets the DQUOT_SUSPENDED flag instead of the DQUOT_USAGE_ENABLED flag, and the quota iteration function ocfs2_get_next_id does not check for the suspended flag, leading to unsafe access. The fix involves setting dqi_priv to NULL after freeing it during remount and adding checks for the DQUOT_SUSPENDED flag in ocfs2_get_next_id to prevent use-after-free. This vulnerability is classified under CWE-416 (Use After Free) and has a CVSS 3.1 base score of 7.8, indicating high severity. Exploitation requires local privileges and low attack complexity, with no user interaction needed. No known exploits are currently reported in the wild. The affected versions correspond to specific Linux kernel commits identified by their hashes, implying that multiple kernel versions incorporating these commits are vulnerable until patched.

For European organizations, this vulnerability poses a significant risk primarily to servers and systems running Linux kernels with OCFS2 filesystems, especially in clustered or enterprise environments where OCFS2 is used for shared storage. Successful exploitation could lead to kernel crashes causing denial of service, or potentially privilege escalation or arbitrary code execution, compromising confidentiality, integrity, and availability of critical systems. This is particularly concerning for sectors relying on high-availability clusters such as finance, telecommunications, and government infrastructure. Since exploitation requires local privileges, the threat is elevated if attackers can gain initial access through other means (e.g., phishing, weak credentials). The vulnerability could be leveraged to escalate privileges or disrupt services, impacting business continuity and data security. Given the widespread use of Linux in European data centers and cloud environments, unpatched systems could be targeted in multi-stage attacks. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, especially as patches are not universally applied yet.

European organizations should prioritize patching Linux kernels to versions that include the fix for CVE-2024-57892. Since the vulnerability is in the OCFS2 filesystem code, organizations should audit their use of OCFS2 and consider migrating to alternative cluster filesystems if feasible. Implement strict access controls to limit local user privileges and reduce the risk of local exploitation. Employ kernel hardening techniques such as Kernel Address Space Layout Randomization (KASLR) and Control Flow Integrity (CFI) to mitigate exploitation impact. Monitor system logs for unusual quota-related syscalls or kernel errors that might indicate exploitation attempts. For environments where immediate patching is not possible, consider disabling OCFS2 mounts or remounting filesystems with read-write options cautiously, avoiding remount as read-only operations that trigger the flaw. Regularly update intrusion detection systems to recognize potential exploitation patterns related to quota syscalls. Finally, ensure robust endpoint security to prevent initial local access by attackers.