CVE-2026-99122

In the Linux kernel, the following vulnerability has been resolved:

vsock/vmci: validate packet source for connected sockets

vmci transport recv stream cb() looks up sockets first by the full source and destination tuple, then by destination only in the bound table. The fallback can select a non-listening socket without checking whether the packet came from its stored peer.

This was reproduced with two VMCI contexts. A RST from the context not stored in a TCP SYN SENT socket reset that socket after it was selected by the destination-only lookup.

VMCI can process notification packets in bottom-half context when the socket is not owned by user context, or defer packets to a workqueue. Use vsock check source() after taking the socket lock in the bottom-half path, and recheck after lock sock() in the workqueue path. Listening sockets continue to accept packets from any source.

Reply with a RST addressed from the received packet before dropping a source that fails validation. This preserves the existing reset behavior for bound non-listening and concurrently closed sockets without directing the reset to a connected socket's stored peer.