CVE-2026-42489: domctl lock open to abuse
[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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Patch Xen Security Advisory 492 v3 (CVE-2026-42489,CVE-2026-42490) - domctl lock open to abuse
Event History
Frequently Asked Questions
What is the severity of CVE-2026-42489?
The severity of CVE-2026-42489 is classified as medium with a CVSS score of 5.3.
What risks are associated with CVE-2026-42489?
CVE-2026-42489 involves risks related to potential abuse of domctl lock operations in the Xen Project.
How do I fix CVE-2026-42489?
To fix CVE-2026-42489, users should apply the relevant patches provided by the Xen Project.
What impact does CVE-2026-42489 have on the Xen Project?
CVE-2026-42489 can lead to unauthorized access or control over virtual machines due to faulty domctl lock management.
Is CVE-2026-42489 exploitable remotely?
CVE-2026-42489 requires certain local conditions to be met, making remote exploitation less likely.