In the Linux kernel, a flaw in the vsock/virtio transport brings about an accept queue count leak. The function that registers a new socket is invoked before the transport type is verified, causing a permanent backlog increment when the transport assignment later fails or switches. As a result, the backlog grows unchecked, and once it surpasses the limit the listener refuses all additional connections, effectively crippling connectivity for that socket. The vulnerability exposes a denial‑of‑service condition tied to resource exhaustion in the kernel.

All Linux kernel installations that have not been updated to include the described commit are vulnerable. The issue originates in the vsock/virtio module, so any system using that transport layer—common in virtualized environments—could be impacted.

The flaw grants a denial‑of‑service without requiring elevated privileges, though it necessitates an ability to trigger connection attempts that fail transport validation. Because the backlog increment is persistent, repeated failures will lock the listener. The CVSS score of 5.5 indicates a medium‑severity risk, and the EPSS score of < 1% suggests a low likelihood of exploitation. However, the potential to disrupt services in environments that rely on vsock connections makes it a high‑priority target for attackers. The vulnerability is not listed in the CISA KEV catalog.