CVE-2026-46207

About vulnerability

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.

Affected product:

AlmaLinux 9.2 ESU , TuxCare 9.6 ESU

Affected packages:

kernel @ 5.14.0 (+1 more)

Live-patch status from KernelCare for each operating system.