CVE-2021-47052 is a vulnerability identified in the Linux kernel's cryptographic subsystem, specifically within the sa2ul module responsible for certain cryptographic operations. The issue is a memory leak caused by two error return paths that fail to free allocated memory for the 'rxd' structure. This flaw results in resource leakage when errors occur, potentially leading to increased memory consumption over time. While the vulnerability does not directly enable code execution or privilege escalation, persistent memory leaks can degrade system performance and stability, especially on systems with high cryptographic workload or long uptimes. The Linux kernel maintainers have addressed this issue by ensuring that all error paths correctly free the allocated memory, preventing the leak. The vulnerability was published in early 2024, with no known exploits in the wild to date. The affected versions correspond to specific Linux kernel commits prior to the patch. No CVSS score has been assigned, and the vulnerability does not appear to require user interaction or authentication to manifest, as it is internal to kernel cryptographic operations.

For European organizations, the impact of CVE-2021-47052 is primarily related to system reliability and availability rather than direct security breaches. Organizations running Linux servers, especially those handling cryptographic workloads such as VPN gateways, secure communications, or cryptographic services, may experience gradual memory exhaustion leading to degraded performance or system crashes if the vulnerability is exploited over time. This could affect critical infrastructure, financial institutions, and government agencies relying on Linux-based systems for secure operations. While the vulnerability does not expose confidential data or allow unauthorized access directly, the resulting instability could cause service disruptions, impacting business continuity and operational efficiency. The absence of known exploits reduces immediate risk, but unpatched systems remain vulnerable to potential future exploitation or accidental resource exhaustion.

European organizations should prioritize updating their Linux kernel to the latest patched versions that address CVE-2021-47052. Kernel updates should be tested in staging environments to ensure compatibility before deployment. Monitoring system memory usage on cryptographic service hosts can help detect abnormal memory growth indicative of exploitation or the underlying leak. Employing automated configuration management and patch management tools can accelerate deployment of the fix across large infrastructures. Additionally, organizations should review cryptographic workload patterns to identify systems at higher risk due to intensive use of the sa2ul module. Implementing resource limits and alerts for memory usage on critical servers can provide early warning signs. Finally, maintaining robust incident response plans to handle potential service degradation or outages will help mitigate operational impacts.