CVE-2024-42157 is a vulnerability identified in the Linux kernel specifically affecting the s390 architecture's pkey (protection key) implementation. The issue arises when the kernel function copy_to_user() fails during an operation involving sensitive data on the stack. In such failure scenarios, the sensitive data is not properly wiped from the stack memory, potentially leaving it exposed to unauthorized access. This vulnerability is related to improper handling of sensitive information in kernel memory, where failure to clear data can lead to information leakage. The patch resolves this by ensuring that sensitive data on the stack is wiped even if copy_to_user() fails, thereby preventing residual sensitive data from remaining accessible in kernel memory. The vulnerability affects specific Linux kernel versions identified by the commit hash e80d4af0a320972aac58e2004d0ba4e44ef4c5c7. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet. The vulnerability is technical and low-level, involving kernel memory management and data sanitization on failure paths, which is critical for maintaining confidentiality of sensitive data handled by the kernel on s390 systems.

For European organizations, the impact of CVE-2024-42157 depends largely on the deployment of Linux systems running on s390 architecture hardware, which is IBM's mainframe platform. Organizations using s390 Linux systems for critical workloads, such as financial institutions, government agencies, and large enterprises, could be at risk of sensitive data leakage if this vulnerability is exploited. The exposure of sensitive kernel stack data could lead to unauthorized disclosure of confidential information, potentially including cryptographic keys or other protected data processed by the kernel. While the vulnerability does not directly enable code execution or privilege escalation, the confidentiality breach could facilitate further attacks or data exfiltration. Given that s390 systems are often used in high-security environments, the risk to data confidentiality is significant. However, the lack of known exploits and the specialized hardware platform limit the immediate widespread impact. European organizations relying on s390 Linux systems should consider this vulnerability seriously, especially in sectors with stringent data protection requirements such as finance, healthcare, and government.

To mitigate CVE-2024-42157, European organizations should promptly apply the official Linux kernel patches that address this vulnerability. Since the issue is specific to the s390 architecture, organizations should verify if their Linux kernel versions correspond to the affected commit hashes and upgrade to patched versions. Additionally, organizations should audit their s390 Linux systems to identify any instances where copy_to_user() failure paths might expose sensitive data and ensure that kernel memory sanitization best practices are enforced. Employing kernel hardening techniques and monitoring for unusual kernel memory access patterns can help detect potential exploitation attempts. Organizations should also maintain strict access controls to s390 systems to limit exposure. Given the specialized nature of the affected platform, collaboration with hardware and OS vendors for timely patch deployment and validation is recommended. Finally, integrating this vulnerability into the organization's vulnerability management and incident response processes will ensure ongoing awareness and readiness.