xen-netback: reject zero-queue configuration from guest

Summary

CVECVE-2026-45890
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-27 14:17:03 UTC
Updated2026-05-27 14:48:31 UTC
DescriptionIn 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.

Risk And Classification

EPSS: 0.000240000 probability, percentile 0.073770000 (date 2026-05-28)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 8d3d53b3e43363e79ab9a9ecc149b06c1314b25d 2993e0f904c45f8af12917344bb1cac7ccd05a60 git Not specified
CNA Linux Linux affected 8d3d53b3e43363e79ab9a9ecc149b06c1314b25d 787bfa423228c4b02ba3368128f625d579085353 git Not specified
CNA Linux Linux affected 8d3d53b3e43363e79ab9a9ecc149b06c1314b25d ce66d6786de45b7ed9cbbdc0988054bf09e58f54 git Not specified
CNA Linux Linux affected 8d3d53b3e43363e79ab9a9ecc149b06c1314b25d 88b0fced1bbbfdb356a007592604008ffc93a6a1 git Not specified
CNA Linux Linux affected 8d3d53b3e43363e79ab9a9ecc149b06c1314b25d ec4859ac5c933e3315543a61adc1ca4358006a41 git Not specified
CNA Linux Linux affected 8d3d53b3e43363e79ab9a9ecc149b06c1314b25d 654780dee9eae419e1648ea58462c4efe54518fa git Not specified
CNA Linux Linux affected 8d3d53b3e43363e79ab9a9ecc149b06c1314b25d d99f69ddc70fd9f4b8148add62209a1a8eb5c615 git Not specified
CNA Linux Linux affected 8d3d53b3e43363e79ab9a9ecc149b06c1314b25d 6d1dc8014334c7fb25719999bca84d811e60a559 git Not specified
CNA Linux Linux affected 3.16 Not specified
CNA Linux Linux unaffected 3.16 semver Not specified
CNA Linux Linux unaffected 5.10.252 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.202 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.165 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.128 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.75 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.14 6.18.* semver Not specified
CNA Linux Linux unaffected 6.19.4 6.19.* semver Not specified
CNA Linux Linux unaffected 7.0 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/787bfa423228c4b02ba3368128f625d579085353 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ce66d6786de45b7ed9cbbdc0988054bf09e58f54 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d99f69ddc70fd9f4b8148add62209a1a8eb5c615 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/654780dee9eae419e1648ea58462c4efe54518fa 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2993e0f904c45f8af12917344bb1cac7ccd05a60 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6d1dc8014334c7fb25719999bca84d811e60a559 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/88b0fced1bbbfdb356a007592604008ffc93a6a1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ec4859ac5c933e3315543a61adc1ca4358006a41 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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