CVE-2026-62427
Deferred Deferred - Pending Action

Xen Control Domain Privilege Escalation via Unfair Locking

Publication date: 2026-07-28

Last updated on: 2026-07-28

Assigner: Xen Project

Description
[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] To manage the system, sysctl and platform operations are used by the control domain or a possible Xenstore domain. Some of these operations may not be executed in parallel, so a system-wide lock each is used. The way those locks are acquired is, however, not providing any fairness. Furthermore, with XSM/Flask in use, the lock acquire will, for some operations, occur ahead of any permission checking. The sysctl issue is CVE-2026-62426. The platform-op issue is CVE-2026-62427.

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Meta Information

Published
2026-07-28
Last Modified
2026-07-28
Generated
2026-08-18
AI Q&A
2026-07-28
EPSS Evaluated
2026-08-16
NVD
CVE-2026-62427
EUVD
EUVD-2026-49778

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
xen sysctl *
xen platform_operations *
xen xen *
xen xen From 4.0 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-305 The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.
CWE-284 The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Attack-Flow Graph

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Executive Summary

CVE-2026-62427 involves a lack of fairness in acquiring system-wide locks for platform operations in Xen. These locks are used by the control domain or a Xenstore domain to manage the system. The issue occurs because the lock acquisition process does not ensure fairness, and in some cases with XSM/Flask enabled, permission checks happen after the lock is acquired.

Detection Guidance

Detection requires checking for unfair lock acquisition in sysctl or platform operations. Review Xen logs for stalled operations or permission-related delays. No direct commands are provided in the context.

Impact Analysis

This vulnerability could lead to denial-of-service conditions where legitimate operations are blocked unfairly. It may also allow unauthorized access to sensitive operations if XSM/Flask is in use, as permission checks occur too late in the process.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it relates to system locking and permission checks in Xen hypervisor operations. It primarily poses a risk of Denial of Service (DoS) due to unfair lock acquisition, which could impact system availability rather than data protection or privacy.

Mitigation Strategies

Apply available patches for CVE-2026-62427 provided by Xen Project. Update Flask policies if using custom configurations. Check Xen versions from 4.0 onwards for affected systems.

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