CVE-2023-52619 is a vulnerability identified in the Linux kernel's pstore/ram subsystem. The issue arises when the number of CPU cores is set to an odd number, such as 7. Under these conditions, the zone size used for memory mapping becomes an odd number, which leads to the calculation of zone addresses that are not properly aligned in virtual memory. Specifically, the addresses for zones 1, 3, 5, 7, etc., become non-aligned virtual addresses. This misalignment causes crashes when the system attempts to access these virtual addresses. The root cause is that the zone size is not being aligned down to an even number, which is necessary to maintain proper memory alignment. The fix involves using the ALIGN_DOWN() macro to ensure the zone size is always even, preventing the creation of non-aligned virtual addresses and thus avoiding the crash. This vulnerability is a stability and availability issue within the Linux kernel, affecting systems that adjust CPU core counts to odd numbers and use the pstore/ram feature. There are no known exploits in the wild at this time, and no CVSS score has been assigned yet. The vulnerability was published on March 18, 2024, and affects specific Linux kernel versions identified by commit hashes.

For European organizations, the primary impact of CVE-2023-52619 is on system stability and availability. Systems running Linux kernels with the vulnerable pstore/ram implementation and configured with an odd number of CPU cores may experience kernel crashes, leading to unexpected downtime or service interruptions. This can affect critical infrastructure, servers, and embedded systems that rely on Linux for continuous operation. While this vulnerability does not directly compromise confidentiality or integrity, the resulting crashes can disrupt business operations, cause data loss if systems are not properly backed up, and increase operational costs due to downtime and troubleshooting. Organizations with high-availability requirements, such as financial institutions, healthcare providers, and industrial control systems in Europe, could face significant operational risks if affected systems are not patched promptly. The lack of known exploits reduces immediate risk, but the vulnerability's presence in widely used Linux kernels means that unpatched systems remain vulnerable to stability issues.

To mitigate CVE-2023-52619, European organizations should: 1) Identify and inventory Linux systems using the affected kernel versions, especially those configured with an odd number of CPU cores and utilizing the pstore/ram feature. 2) Apply the official Linux kernel patches that incorporate the ALIGN_DOWN() fix as soon as they become available from trusted sources or Linux distributions. 3) Avoid configuring systems with an odd number of CPU cores where possible until patches are applied, as a temporary workaround to prevent triggering the vulnerability. 4) Implement robust monitoring and alerting for kernel crashes and system instability to detect potential exploitation or triggering of this bug early. 5) Test patches in staging environments to ensure compatibility and stability before wide deployment. 6) Maintain regular backups and disaster recovery plans to minimize data loss and downtime in case of crashes. 7) Engage with Linux distribution vendors and security advisories to stay informed about updates and related vulnerabilities.