CVE-2026-45890
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| debian | bookworm | fixed | 6.1.170-1 |
| debian | bullseye | fixed | 5.10.257-1 |
| debian | forky | fixed | 6.18.14-1 |
| debian | sid | fixed | 6.18.14-1 |
| debian | trixie | fixed | 6.12.85-1 |
| sles | affected | |
References
- https://git.kernel.org/stable/c/2993e0f904c45f8af12917344bb1cac7ccd05a60
- https://git.kernel.org/stable/c/787bfa423228c4b02ba3368128f625d579085353
- https://git.kernel.org/stable/c/ce66d6786de45b7ed9cbbdc0988054bf09e58f54
- https://git.kernel.org/stable/c/88b0fced1bbbfdb356a007592604008ffc93a6a1
- https://git.kernel.org/stable/c/ec4859ac5c933e3315543a61adc1ca4358006a41
- https://git.kernel.org/stable/c/654780dee9eae419e1648ea58462c4efe54518fa
- https://git.kernel.org/stable/c/d99f69ddc70fd9f4b8148add62209a1a8eb5c615
- https://git.kernel.org/stable/c/6d1dc8014334c7fb25719999bca84d811e60a559
- https://security-tracker.debian.org/tracker/CVE-2026-45890
- https://www.suse.com/security/cve/CVE-2026-45890.html
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.