Threats Tagged 'cve-2026-45890'

A vulnerability in the Linux kernel's Xen network backend allows a malicious or buggy Xen guest to configure zero queues, which is invalid per the Xen network interface specification. This improper input leads to a kernel warning and can cause a denial of service on hosts configured to panic on warnings. The issue arises because the backend only validates the upper bound of requested queues but not zero, allowing a zero value to trigger a kernel warning and potential host panic.

In the Linux kernel, the following vulnerability has been resolved: xen-netback: reject zero-queue configuration from guest A malicious or buggy Xen guest can write "0" to the xenbus key "multi-queue-num-queues". The connect() function in the backend only validates the upper bound (requested_num_queues > xenvif_max_queues) but not zero, allowing requested_num_queues=0 to reach vzalloc(array_size(0, sizeof(struct xenvif_queue))), which triggers WARN_ON_ONCE(!size) in __vmalloc_node_range(). On systems with panic_on_warn=1, this allows a guest-to-host denial of service. The Xen network interface specification requires the queue count to be "greater than zero". Add a zero check to match the validation already present in xen-blkback, which has included this guard since its multi-queue support was added.