CVE-2024-39494 is a use-after-free vulnerability identified in the Linux kernel's Integrity Measurement Architecture (IMA) subsystem. The flaw arises from improper handling of the dentry structure's d_name.name field during rename operations. Specifically, the d_name.name pointer can change when a file or directory is renamed, and the previous value may be freed without proper synchronization. Although there are locking mechanisms available in the kernel (such as d_lock on the dentry and its parent, i_rwsem exclusive lock on the parent's inode, and rename_lock) that could stabilize the name pointer, these locks are not consistently applied at all relevant code sites. Consequently, the system may take a reference to a freed memory region, leading to a use-after-free condition. This vulnerability could potentially be exploited to cause kernel memory corruption, leading to system instability, crashes (denial of service), or in some cases, privilege escalation if an attacker can manipulate kernel memory. The vulnerability affects multiple versions of the Linux kernel, as indicated by the repeated commit hashes, and was publicly disclosed on July 12, 2024. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet. The fix involves taking a stable snapshot of the d_name.name to prevent referencing freed memory during rename operations.

For European organizations, the impact of CVE-2024-39494 could be significant, especially for those relying heavily on Linux-based infrastructure, including servers, cloud environments, and embedded systems. The vulnerability could allow local attackers or malicious processes to trigger use-after-free conditions, potentially leading to kernel crashes and denial of service, disrupting critical services. In worst-case scenarios, skilled attackers might leverage this flaw to escalate privileges to root, compromising system integrity and confidentiality. This is particularly critical for sectors such as finance, healthcare, government, and critical infrastructure, where Linux systems are prevalent and uptime and data integrity are paramount. Additionally, organizations using containerized environments or virtualized Linux hosts may face increased risk if the kernel is vulnerable, as exploitation could affect multiple tenants or services. Although no active exploits are known, the presence of this vulnerability in widely deployed Linux kernels necessitates prompt attention to avoid future targeted attacks.

To mitigate CVE-2024-39494 effectively, European organizations should: 1) Apply the official Linux kernel patches as soon as they become available from trusted sources or distribution vendors to ensure the vulnerability is remediated. 2) Prioritize patching in production environments running vulnerable kernel versions, especially those exposed to untrusted users or processes. 3) Implement strict access controls to limit the ability of unprivileged users to execute code or perform rename operations on critical files, reducing the attack surface. 4) Monitor kernel logs and system behavior for signs of instability or unusual crashes that could indicate exploitation attempts. 5) For environments where immediate patching is not feasible, consider temporary mitigations such as restricting rename operations or isolating vulnerable systems. 6) Maintain an up-to-date inventory of Linux kernel versions in use to identify and prioritize vulnerable systems. 7) Engage with Linux distribution vendors for timely security updates and advisories. 8) Employ kernel hardening techniques and security modules (e.g., SELinux, AppArmor) to limit the impact of potential exploits.