CVE-2024-42155 addresses a vulnerability in the Linux kernel specifically related to the s390 architecture's handling of protected and secure keys (pkey). The vulnerability arises because copies of these sensitive keys, although their clear-key material is not directly accessible, remain on the stack even in error conditions. This residual presence on the stack means that key material intended to be visible only to the calling process could potentially be exposed inadvertently to other processes or through memory disclosure attacks. The patch resolves this by ensuring that all copies of protected and secure keys are wiped from the stack, including in error scenarios, thereby reducing the risk of key leakage. This vulnerability is subtle and specific to the s390 platform, which is IBM's mainframe architecture supported by the Linux kernel. The issue does not have any known exploits in the wild at the time of publication and no CVSS score has been assigned yet. The vulnerability primarily impacts confidentiality by potentially exposing cryptographic key material, which could undermine the security guarantees of cryptographic operations relying on these keys.

For European organizations, the impact of CVE-2024-42155 depends largely on their use of Linux systems running on s390 architecture, which is less common than x86 or ARM but prevalent in enterprise mainframe environments. Organizations in sectors such as finance, government, and large-scale enterprise IT that rely on IBM mainframes for critical workloads could be at risk if they use vulnerable kernel versions. Exposure of protected or secure keys could lead to unauthorized access to encrypted data or cryptographic operations, potentially compromising confidentiality and trust in secure communications or data protection mechanisms. Although no active exploitation is reported, the presence of residual key material in memory increases the attack surface for sophisticated threat actors capable of memory inspection or side-channel attacks. This could be particularly concerning for organizations handling sensitive personal data under GDPR, as any compromise of cryptographic keys could lead to data breaches with regulatory and reputational consequences.

To mitigate this vulnerability, European organizations using Linux on s390 architectures should promptly apply the kernel patch that wipes copies of protected and secure keys from the stack, including in error paths. System administrators should verify that their Linux kernel versions are updated to include this fix. Additionally, organizations should audit their cryptographic key management practices to ensure keys are handled securely and minimize exposure in memory. Employing kernel hardening techniques such as stack canaries, memory encryption, and restricting access to kernel memory can further reduce risk. Monitoring for unusual memory access patterns or attempts to dump kernel memory may help detect exploitation attempts. Given the specificity of this vulnerability, organizations should also assess whether they have legacy or unsupported kernel versions in use and plan for timely upgrades. Finally, maintaining strict access controls and limiting privileged user access reduces the likelihood of key material exposure through insider threats or compromised accounts.