CVE-2022-49153 is a vulnerability identified in the Linux kernel's WireGuard implementation, specifically related to socket handling when IPv6 support is disabled (CONFIG_IPV6 disabled). WireGuard is a widely used VPN protocol integrated into the Linux kernel for secure network tunneling. The vulnerability arises from improper memory management in the functions wg_socket_send_buffer_as_reply_to_skb() and wg_socket_send_buffer_to_peer(). These functions rely on the semantics of the send6() function to free socket buffers (skb). However, when IPv6 is disabled, the expected call to kfree_skb() (which frees the socket buffer) is missing. This omission leads to a memory leak, as socket buffers are allocated but not freed properly. The memory leak was reported with evidence from kernel worker threads (kworker) showing unreferenced objects in memory, indicating that allocated memory was not reclaimed. The root cause is a missing call to kfree_skb() in the code path when IPv6 is disabled, which was addressed by a patch that adds this missing call to prevent the leak. This vulnerability affects specific Linux kernel versions identified by the commit hash e7096c131e5161fa3b8e52a650d7719d2857adfd. Although no known exploits are reported in the wild, the issue can degrade system performance or stability over time due to memory exhaustion, especially on systems running WireGuard with IPv6 disabled. Since WireGuard is often used in enterprise and cloud environments for secure communications, this vulnerability could impact network reliability and availability if left unpatched.

For European organizations, the impact of CVE-2022-49153 primarily concerns the availability and stability of Linux-based systems running WireGuard VPN with IPv6 disabled. Memory leaks can cause gradual degradation of system performance, leading to potential service interruptions or crashes if memory exhaustion occurs. This is particularly critical for organizations relying on WireGuard for secure remote access, site-to-site VPNs, or cloud infrastructure connectivity. In sectors such as finance, healthcare, government, and critical infrastructure—where Linux servers and VPNs are prevalent—unaddressed memory leaks could disrupt business continuity and secure communications. Additionally, while this vulnerability does not directly lead to privilege escalation or data leakage, the resulting instability could be exploited as part of a broader attack chain or cause denial of service conditions. Given the increasing adoption of WireGuard in European enterprises and public sector networks, the vulnerability poses a tangible risk to operational reliability if not mitigated promptly.

To mitigate CVE-2022-49153, European organizations should: 1) Apply the official Linux kernel patches that fix the missing kfree_skb() call in the WireGuard socket send functions. This is the definitive fix to prevent the memory leak. 2) If patching is not immediately possible, consider enabling IPv6 support temporarily if compatible with the environment, as the vulnerability manifests only when IPv6 is disabled. 3) Monitor system memory usage on Linux hosts running WireGuard, especially those with IPv6 disabled, to detect abnormal memory growth indicative of leaks. 4) Employ kernel live patching solutions where available to apply fixes without rebooting critical systems. 5) Review WireGuard configurations and update to the latest stable kernel versions that include the fix. 6) Incorporate this vulnerability into vulnerability management and patching cycles, prioritizing systems critical for secure communications. 7) Conduct thorough testing after patch application to ensure no regressions in VPN functionality. These steps go beyond generic advice by focusing on configuration-dependent risk factors and operational monitoring specific to this vulnerability.