CVE-2025-21669

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

vsock/virtio: discard packets if the transport changes

If the socket has been de-assigned or assigned to another transport, we must discard any packets received because they are not expected and would cause issues when we access vsk->transport.

A possible scenario is described by Hyunwoo Kim in the attached link, where after a first connect() interrupted by a signal, and a second connect() failed, we can find vsk->transport at NULL, leading to a NULL pointer dereference.

This vulnerability is rated as Moderate because exploitation requires local unprivileged access and is restricted to causing a denial of service via a kernel crash, without impacting confidentiality or data integrity. The issue stems from improper handling of packets when virtual socket transport bindings change, leading to a null pointer dereference during interrupted or failed connection sequences. Red Hat Enterprise Linux systems are primarily exposed when virtual machine or container communication utilizing the virtio VSOCK transport is active, and the flaw cannot be reached by unauthenticated remote network attackers.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.