CVE-2026-45890
Published: May 27, 2026· Updated: May 27, 2026
Official Description
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.
Technical Analysis
CVE-2026-45890 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
Affected Vendors & Products
Exploit & PoC Resources
All References (8)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-45890 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts