CVE-2021-47190 is a vulnerability identified in the Linux kernel's performance monitoring subsystem, specifically within the 'perf' tool's handling of BPF (Berkeley Packet Filter) related BTF (BPF Type Format) data. The issue arises in the function perf_env__insert_btf(), which is responsible for inserting BTF data into the environment. The vulnerability manifests as a memory leak when a duplicate BTF ID is encountered. Instead of properly handling the duplicate and freeing allocated memory, the function fails to do so, leading to unreleased memory consumption. The patch modifies perf_env__insert_btf() to return a success or error code and ensures that memory is freed if insertion does not occur. Additionally, a return value of -1 was added to perf_env__fetch_btf() to indicate insertion errors, although this return value is not currently checked by the caller. This vulnerability does not appear to allow direct code execution or privilege escalation but can cause resource exhaustion due to memory leaks. The affected versions are specific Linux kernel commits identified by their hashes, indicating that this is a recent and targeted fix. No known exploits are reported in the wild, and the vulnerability was published in April 2024. The lack of a CVSS score suggests it is a low to medium severity issue primarily affecting system stability rather than security confidentiality or integrity directly.

For European organizations, the impact of CVE-2021-47190 is primarily related to system reliability and availability. Linux is widely used across European enterprises, especially in servers, cloud infrastructure, and embedded systems. A memory leak in the perf subsystem could lead to gradual resource depletion, potentially causing performance degradation or system crashes if the perf tool is heavily used or if BPF programs are frequently loaded. This could affect monitoring, debugging, and performance analysis workflows, which are critical for maintaining operational stability. While the vulnerability does not directly expose sensitive data or allow unauthorized access, the indirect impact on availability could disrupt business-critical services. Organizations relying on Linux for high-availability environments or real-time monitoring may experience increased operational risk if the vulnerability is not patched. However, since exploitation requires specific conditions (use of perf with BPF and encountering duplicate BTF IDs), the scope is somewhat limited. The absence of known exploits reduces immediate risk but does not eliminate the need for remediation.

European organizations should prioritize applying the patch that addresses this memory leak in the Linux kernel's perf subsystem. Since the vulnerability is in the kernel, updating to the latest stable kernel version that includes the fix is the most effective mitigation. For environments where immediate kernel upgrades are challenging, organizations should consider limiting the use of perf and BPF tools, especially automated or frequent BPF loading that could trigger the leak. Monitoring system memory usage and perf-related logs can help detect abnormal resource consumption early. Additionally, organizations should implement kernel live patching solutions where available to minimize downtime during updates. Security teams should also review their incident response plans to include scenarios involving resource exhaustion and ensure that system monitoring tools are configured to alert on unusual memory usage patterns. Finally, maintaining an inventory of Linux kernel versions deployed across infrastructure will aid in rapid identification of vulnerable systems.