CVE-2025-39718: Out-of-bounds Write

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

vsock/virtio: Validate length in packet header before skb_put()

When receiving a vsock packet in the guest, only the virtqueue buffer size is validated prior to virtio_vsock_skb_rx_put(). Unfortunately, virtio_vsock_skb_rx_put() uses the length from the packet header as the length argument to skb_put(), potentially resulting in SKB overflow if the host has gone wonky.

Validate the length as advertised by the packet header before calling virtio_vsock_skb_rx_put().