CVE-2026-45890

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.

• linux linux kernel (>= 3.16 < 5.10.252) • linux linux kernel (>= 5.11 < 5.15.202) • linux linux kernel (>= 5.16 < 6.1.165) • linux linux kernel (>= 6.2 < 6.6.128) • linux linux kernel (>= 6.7 < 6.12.75) • linux linux kernel (>= 6.13 < 6.18.14) • linux linux kernel (>= 6.19 < 6.19.4)