CVE-2021-47298 is a vulnerability identified in the Linux kernel's BPF (Berkeley Packet Filter) sockmap implementation. The issue arises from a potential memory leak occurring during an unlikely error case in the skb_linearize function. Specifically, when skb_linearize is required but fails, the kernel could leak a socket buffer message (msg) during error handling because the message block is not freed properly. The fix involves ensuring that the message block is explicitly freed (kfree) before returning the error, thus preventing the memory leak. This vulnerability was discovered during a code review and affects certain versions of the Linux kernel identified by specific commit hashes. No known exploits are currently reported in the wild, and no CVSS score has been assigned to this vulnerability yet.

For European organizations, the impact of CVE-2021-47298 is primarily related to resource exhaustion and potential system instability. Although this vulnerability does not directly allow for privilege escalation, remote code execution, or data leakage, the memory leak could lead to gradual degradation of system performance or denial of service (DoS) conditions if exploited repeatedly or under heavy network load. Systems running Linux kernels with the affected BPF sockmap code, especially those involved in network packet processing, firewalling, or container orchestration, may experience increased memory consumption. This could affect critical infrastructure, cloud services, and enterprise environments relying on Linux-based servers. Given the widespread use of Linux in European data centers, telecom infrastructure, and government systems, unpatched systems could face reliability issues, impacting availability and operational continuity.

To mitigate this vulnerability, European organizations should prioritize updating their Linux kernel to the latest patched versions where this memory leak has been fixed. Specifically, system administrators should: 1) Identify all Linux systems running affected kernel versions, especially those utilizing BPF sockmap features. 2) Apply vendor-provided kernel patches or upgrade to a kernel version that includes the fix for CVE-2021-47298. 3) Monitor system memory usage and kernel logs for unusual patterns that might indicate attempts to trigger the memory leak. 4) Employ network segmentation and limit exposure of critical Linux servers to untrusted networks to reduce the risk of exploitation. 5) For environments using container orchestration platforms like Kubernetes, ensure the underlying nodes are patched, as these often leverage BPF for networking. 6) Maintain a robust patch management process to quickly deploy kernel updates and validate system integrity post-update.