CVE-2024-42067 is a vulnerability identified in the Linux kernel related to the handling of memory protection in the Berkeley Packet Filter (BPF) Just-In-Time (JIT) compiler subsystem. Specifically, the issue arises from the function set_memory_rox(), which is intended to set memory pages as read-only and executable (ROX). The vulnerability occurs because the return value of set_memory_rox() was not properly checked by the bpf_jit_binary_lock_ro() function. If set_memory_rox() fails, the memory intended to be protected remains writable and executable, potentially allowing an attacker to modify JIT-compiled BPF code after it has been locked, violating expected memory protections. This could lead to unauthorized code execution or privilege escalation within the kernel. The fix involves adding proper error checking to bpf_jit_binary_lock_ro() to ensure that if set_memory_rox() fails, the process aborts rather than continuing with unprotected memory. This vulnerability affects Linux kernel versions identified by the commit hash 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and potentially other versions sharing this code path. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet. However, due to the nature of the vulnerability involving kernel memory protection and the BPF JIT compiler, it represents a significant security risk if exploited.

For European organizations, this vulnerability poses a risk primarily to systems running vulnerable Linux kernel versions with BPF JIT enabled. The BPF subsystem is widely used for network packet filtering, performance monitoring, and security enforcement, making it a critical component in many enterprise and cloud environments. Exploitation could allow attackers to execute arbitrary code at the kernel level, leading to full system compromise, data breaches, or disruption of critical services. This is particularly concerning for sectors with high reliance on Linux infrastructure such as telecommunications, finance, government, and cloud service providers across Europe. The ability to bypass memory protection mechanisms undermines the kernel's security model, increasing the risk of privilege escalation and persistent threats. Although no active exploits are known, the vulnerability's presence in the kernel means that attackers with local access or the ability to run BPF programs could leverage it to escalate privileges or evade security controls, impacting confidentiality, integrity, and availability of systems.

European organizations should prioritize updating their Linux kernels to versions where this vulnerability is patched. Since the issue involves kernel memory protection in the BPF JIT compiler, disabling BPF JIT compilation temporarily can serve as an interim mitigation if immediate patching is not feasible. System administrators should audit their environments to identify systems running vulnerable kernel versions and confirm whether BPF JIT is enabled. Applying kernel updates from trusted vendors or distributions that have incorporated the fix is critical. Additionally, organizations should enforce strict access controls to limit which users or processes can load or execute BPF programs, reducing the attack surface. Monitoring for unusual kernel-level activity or unexpected BPF program loading can help detect exploitation attempts. Finally, integrating this vulnerability into vulnerability management and patching workflows will ensure timely remediation and reduce exposure.