Vulnerability in Xen

CVE-2026-42489

[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] To create and manage guests, domctl operations are used by the control domain, a possible Xenstore domain, or by a domain controlling a particular guest. Some of these operations may not be executed in parallel, so a system-wide lock is used. The way that lock is acquired is, however, not providing any fairness. This is CVE-2026-42489. Furthermore, with XSM/Flask in use, the lock acquire will, for some operations, occur ahead of any permission checking. This is CVE-2026-42490.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.001 (0.7th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 1st percentile — 0.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-42489: held from 0.001 to 0.001.

EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000

Affected products

  • Xen — versions consult Xen advisory XSA-492

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-42489?
CVE-2026-42489 is a medium-severity vulnerability in Xen, classified under Improper Locking. CVSS score: 5.3/10. Published 2026-06-18.
How severe is CVE-2026-42489?
Medium severity. CVSS v3 base score is 5.3 out of 10.