CVE-2024-42158 addresses a vulnerability in the Linux kernel specifically related to the s390 architecture's pkey (protection key) implementation. The issue involves improper handling of sensitive memory deallocation functions. The vulnerability was identified through warnings generated by Coccinelle, a tool used for matching and transforming C code, which highlighted opportunities to use more secure memory zeroing and freeing functions. The patch replaces the use of memzero_explicit() and kfree() with kfree_sensitive() in the kernel code. kfree_sensitive() is designed to securely zero out memory before freeing it, preventing potential leakage of sensitive data that might remain in memory after deallocation. The affected code lines (1506, 1643, 1770) indicate multiple instances where sensitive data could have been improperly handled. Although no known exploits are currently reported in the wild, the vulnerability could theoretically allow attackers with kernel-level access or the ability to execute code in kernel context on s390 systems to recover sensitive information from freed memory. This vulnerability is architecture-specific (IBM s390 mainframe architecture) and relates to kernel memory management security best practices rather than a direct remote code execution or privilege escalation flaw. The Linux kernel versions affected are identified by specific commit hashes, indicating the issue was present in certain recent kernel snapshots before the patch was applied. The absence of a CVSS score suggests the vulnerability is considered low risk in terms of exploitation complexity and impact scope but still important for secure kernel operation on affected platforms.

For European organizations, the impact of CVE-2024-42158 is primarily relevant to those operating IBM s390 mainframe systems running Linux kernels vulnerable to this issue. Such systems are typically used in large enterprises, financial institutions, and government agencies for critical workloads. The vulnerability could lead to potential leakage of sensitive information from kernel memory if exploited, which may compromise confidentiality. However, exploitation requires privileged access or kernel-level code execution, limiting the risk of widespread attacks. The integrity and availability of systems are not directly affected by this vulnerability. Organizations relying on s390 Linux systems should consider this vulnerability in their risk assessments, especially if they handle sensitive or regulated data. Given the specialized nature of the affected architecture, the broader European IT infrastructure, which predominantly uses x86_64 architectures, is less impacted. Nonetheless, for sectors using mainframe technology, failure to patch could expose sensitive data and undermine compliance with data protection regulations such as GDPR.

To mitigate CVE-2024-42158, organizations should: 1) Identify all Linux systems running on the s390 architecture within their environment. 2) Apply the official Linux kernel patches that replace memzero_explicit() and kfree() with kfree_sensitive() in the affected kernel versions. This may require updating to a newer kernel release or backporting the patch if using long-term support kernels. 3) Conduct thorough testing of patched kernels in staging environments to ensure stability and compatibility with existing workloads. 4) Implement strict access controls and monitoring on s390 systems to prevent unauthorized kernel-level access, reducing the risk of exploitation. 5) Regularly audit kernel memory handling practices and use static analysis tools like Coccinelle to detect similar issues proactively. 6) Maintain an up-to-date inventory of hardware architectures and kernel versions to quickly respond to architecture-specific vulnerabilities. 7) Engage with Linux distribution vendors or mainframe support providers for guidance and timely patch deployment.