CVE-2026-62426
Received Received - Intake

Xen Control Domain Privilege Escalation via Unfair Lock Acquisition

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
2026-07-28
AI Q&A
2026-07-28
EPSS Evaluated
N/A
NVD
CVE-2026-62426
EUVD
EUVD-2026-49777

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
xen xen From 4.0 (inc)
xen xen *
xen flask *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

CVE-2026-62426 is a vulnerability in Xen versions from 4.0 onwards where sysctl operations lack a fair locking mechanism. This allows a less privileged entity to stall a more privileged one, potentially causing a Denial of Service (DoS) affecting the entire host. The issue occurs because locks are acquired without fairness and permission checks may happen after the lock is acquired.

Detection Guidance

Detecting CVE-2026-62426 requires checking for improper sysctl lock fairness in Xen versions 4.0 and later. Monitor for unusual delays in privileged operations or DoS conditions. Review system logs for stalled sysctl operations. Apply available patches from Xen Project advisories.

Impact Analysis

This vulnerability can lead to a Denial of Service (DoS) where a less privileged user or process can stall more privileged operations, potentially disrupting the entire host system. This could result in system unavailability or degraded performance for all users and services.

Compliance Impact

This vulnerability primarily causes Denial of Service (DoS) conditions by allowing less privileged entities to stall more privileged ones. It does not directly impact data confidentiality or integrity, which are key focus areas for GDPR and HIPAA. However, prolonged DoS conditions could indirectly affect compliance by disrupting system availability required for regulated operations.

Mitigation Strategies

Apply available patches for CVE-2026-62426 from Xen Project. Update Flask policies if using custom configurations. No known mitigation exists besides patching.

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