CVE-2026-46207

/// Technical description

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

vsock/virtio: fix empty payload in tap skb for non-linear buffers

For non-linear skbs, virtio_transport_build_skb() goes through

virtio_transport_copy_nonlinear_skb() to copy the original payload

in the new skb to be delivered to the vsockmon tap device.

This manually initializes an iov_iter but does not set iov_iter.count.

Since the iov_iter is zero-initialized, the copy length is zero and no

payload is actually copied to the monitor interface, leaving data

un-initialized.

Fix this by removing the linear vs non-linear split and using

skb_copy_datagram_iter() with iov_iter_kvec() for all cases, as

vhost-vsock already does. This handles both linear and non-linear skbs,

properly initializes the iov_iter, and removes the now unused

virtio_transport_copy_nonlinear_skb().

While touching this code, let's also check the return value of

skb_copy_datagram_iter(), even though it's unlikely to fail.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References