CVE-2026-45890
xen-netback: reject zero-queue configuration from guest
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.
INFO
Published Date :
May 27, 2026, 2:17 p.m.
Last Modified :
May 27, 2026, 2:48 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel with the provided patch.
- Ensure queue count is greater than zero.
- Apply validation logic to xen-netback.
- Reinforce guest input validation.
Public PoC/Exploit Available at Github
CVE-2026-45890 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
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CVE-2026-45890.
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Common Attack Pattern Enumeration and Classification (CAPEC)
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weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 27, 2026
Action Type Old Value New Value Added 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. Added Reference https://git.kernel.org/stable/c/2993e0f904c45f8af12917344bb1cac7ccd05a60 Added Reference https://git.kernel.org/stable/c/654780dee9eae419e1648ea58462c4efe54518fa Added Reference https://git.kernel.org/stable/c/6d1dc8014334c7fb25719999bca84d811e60a559 Added Reference https://git.kernel.org/stable/c/787bfa423228c4b02ba3368128f625d579085353 Added Reference https://git.kernel.org/stable/c/88b0fced1bbbfdb356a007592604008ffc93a6a1 Added Reference https://git.kernel.org/stable/c/ce66d6786de45b7ed9cbbdc0988054bf09e58f54 Added Reference https://git.kernel.org/stable/c/d99f69ddc70fd9f4b8148add62209a1a8eb5c615 Added Reference https://git.kernel.org/stable/c/ec4859ac5c933e3315543a61adc1ca4358006a41