The Linux kernel vsock/vmci vulnerability (CVE-2026-53181) involves a sk_ack_backlog resource leak triggered when vmci_transport_recv_connecting_server() returns an error. The function vmci_transport_recv_listen() calls vsock_remove_pending() but omits sk_acceptq_removed(), causing sk_ack_backlog to increment permanently. Repeated handshake failures (due to malformed packets, queue pair allocation failure, or event subscription failure) cause sk_ack_backlog to reach sk_max_ack_backlog, after which the listener silently refuses new connections with -ECONNREFUSED. This denial of service requires a process restart to recover. The fix balances sk_acceptq_added() with sk_acceptq_removed() on the error path to prevent the leak.

The vulnerability causes a denial of service condition by exhausting the socket acknowledgment backlog, leading to permanent refusal of new connection attempts on the affected listener. This impacts availability but does not affect confidentiality or integrity.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The vulnerability description indicates that a fix has been implemented in the Linux kernel source code by balancing socket queue operations on error paths. Until an official patch is available and applied, affected systems may require process restarts to recover from the denial of service condition.