CVE-2026-45890 | xen-netback: reject zero-queue configuration from guest

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.

Published: 2026-05-27 Last update: 2026-05-27 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Conclusion & alert: CVE-2026-45890 is rated Low Risk (7.5/100): low exploitation likelihood (EPSS 0.18%). Mandatory action: Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-45890

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.02% 0.18% +0.15%
2 2026-05-28 0.02%

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-45890

CVSS metrics for this CVE.

No CVSS data in dataset for this CVE.

Weakness enumeration for CVE-2026-45890

GitHub Security Advisory for CVE-2026-45890

GHSA-jc43-3m97-6p35 · Severity: unknown — In the Linux kernel, the following vulnerability has been resolved: xen-netback: reject zero...

OS Trackers for CVE-2026-45890

vendor priority summary link
debian not yet assigned CVE-2026-45890 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-45890
redhat https://access.redhat.com/security/cve/CVE-2026-45890
suse https://www.suse.com/security/cve/CVE-2026-45890/
ubuntu medium CVE-2026-45890 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1422 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 1024, ignored 172, needed 112, released 84, pending 18, not-affected 11, needs-triage 1. https://ubuntu.com/security/CVE-2026-45890

Affected software / configurations for CVE-2026-45890

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-45890

cvelogic Threat Intelligence