CVE-2024-42156 is a vulnerability identified in the Linux kernel, specifically related to the s390 architecture's pkey (protection key) implementation. The vulnerability concerns improper handling of sensitive cryptographic key material during IOCTL operations that convert clear-text keys into protected or secure keys. The issue arises because copies of clear-key structures were not properly wiped from the stack upon failure of these operations, potentially leaving sensitive key data in memory. This residual data could be accessed by an attacker with sufficient privileges, leading to unauthorized disclosure of cryptographic keys. The fix involves wiping all sensitive data from the stack for all relevant IOCTL calls, ensuring that no clear-key material remains accessible after failure conditions. The vulnerability affects specific Linux kernel versions identified by commit hashes, and no known exploits are currently reported in the wild. The vulnerability is specific to the s390 architecture, which is IBM's mainframe platform, indicating a narrower scope of affected systems compared to general Linux distributions on x86 or ARM architectures. No CVSS score has been assigned yet, but the vulnerability relates to sensitive data exposure due to incomplete memory sanitization in kernel code handling cryptographic keys.

For European organizations, the impact of CVE-2024-42156 depends largely on their use of Linux systems running on IBM s390 mainframe hardware. Organizations in sectors such as finance, government, and large enterprises that rely on mainframe systems for critical workloads and sensitive data processing could be at risk. Exposure of cryptographic keys could lead to compromise of encrypted data, undermining confidentiality and potentially allowing attackers to decrypt sensitive communications or data stores. Although exploitation requires privileged access and is limited to a specific architecture, the impact on confidentiality is significant if exploited. The vulnerability does not appear to affect availability or integrity directly but could facilitate further attacks if key material is leaked. Since no exploits are known in the wild, the immediate risk is low, but the presence of sensitive key material in memory after failures represents a latent risk that could be leveraged by attackers with local access or through privilege escalation. European organizations with compliance requirements around data protection and cryptographic key management should prioritize addressing this vulnerability to maintain security posture and regulatory compliance.

European organizations using Linux on s390 mainframe systems should apply the vendor-provided patches or kernel updates that address CVE-2024-42156 as soon as they become available. In the absence of patches, organizations should restrict access to affected systems to trusted administrators only and monitor for unusual activity that could indicate attempts to access kernel memory or cryptographic key material. Implement strict privilege separation and auditing to detect and prevent unauthorized local access. Additionally, organizations should review their cryptographic key management policies to ensure keys are rotated regularly and that key material is protected using hardware security modules (HSMs) or other secure enclaves where possible. Conduct thorough testing of kernel updates in staging environments before deployment to avoid operational disruptions. Finally, maintain awareness of any emerging exploit reports or advisories related to this vulnerability to respond promptly to evolving threats.