CVE-2022-48786 is a vulnerability identified in the Linux kernel's vsock (virtual socket) implementation. The issue arises when a connection attempt via vsock is interrupted by a signal. Specifically, the function vsock_connect() expects that the socket could already be in the TCP_ESTABLISHED state if the connecting task wakes up with a signal pending. In such cases, the socket remains listed in the connected table. However, when the socket state is reset due to the interruption, the socket is not removed from this connected table. Consequently, if the process retries the connect() call and the connection succeeds, the socket is added again to the connected table, resulting in corruption of the linked list managing these connections. This list corruption can lead to undefined behavior within the kernel, potentially causing system instability or crashes. The patch to fix this vulnerability involves calling vsock_remove_connected() when a signal interrupts the connection attempt, ensuring the socket is properly removed from the connected table before retrying. This fix prevents double addition and the resulting list corruption. The patch depends on a prior fix (commit d5afa82c977e) that corrected socket removal from the list, which is present in all current stable Linux kernel trees except version 4.9.y. No known exploits are reported in the wild at this time. The vulnerability affects Linux kernel versions identified by the commit hash d021c344051af91f42c5ba9fdedc176740cbd238 and likely other versions using the vulnerable vsock implementation. Since vsock is used primarily for communication between virtual machines and the host or between containers, this vulnerability is relevant in virtualized and containerized environments.

For European organizations, the impact of CVE-2022-48786 depends largely on their use of Linux-based virtualized or containerized environments that utilize vsock for inter-VM or container-host communication. If exploited, the vulnerability could cause kernel list corruption leading to system instability, crashes, or denial of service conditions. This could disrupt critical services running on virtual machines or containers, affecting availability. While there is no indication that this vulnerability allows privilege escalation or remote code execution directly, the resulting instability could be leveraged as part of a broader attack chain. Organizations running cloud infrastructure, data centers, or edge computing platforms with Linux virtualization stacks are particularly at risk. Given the widespread adoption of Linux in European enterprise and public sector IT infrastructure, especially in cloud and container orchestration platforms, the vulnerability poses a moderate risk to operational continuity. However, the lack of known exploits and the requirement for signal interruption during connection attempts reduce the immediate threat level. Still, unpatched systems may be vulnerable to accidental or maliciously induced denial of service, impacting service availability and potentially causing operational disruptions.

European organizations should prioritize updating their Linux kernels to versions that include the patch for CVE-2022-48786. Specifically, ensure that kernel versions incorporate the fix that calls vsock_remove_connected() upon signal interruption during vsock_connect(). For environments running older kernels, backporting the patch is recommended, provided the prerequisite commit d5afa82c977e is also applied. System administrators should audit their virtualization and container platforms to identify usage of vsock communication and assess exposure. Monitoring for unusual kernel errors or crashes related to vsock connections can help detect exploitation attempts or accidental triggers. Additionally, implementing strict process signal handling policies and limiting unnecessary signal interruptions during critical connection operations can reduce the risk of triggering the vulnerability. For high-security environments, consider isolating critical virtual machines or containers to minimize the impact of potential kernel instability. Regular kernel updates and adherence to vendor security advisories are essential to maintain protection against this and similar vulnerabilities.