Race Condition Vulnerability in Xen Hypervisor Affects HVM and PVH Guests
CVE-2026-23558

7.8HIGH

Key Information:

Vendor

Xen Project
Status
Xen Project
Vendor
CVE Published:
19 May 2026

What is CVE-2026-23558?

A race condition vulnerability exists in the Xen Hypervisor, where concurrent operations between HVM or PVH guests and grant table version changes can lead to unexpected behavior. When a guest alters the grant table version from v2 to v1 while simultaneously mapping status pages, it is possible for some status pages to be deallocated while their mappings remain in the guest's secondary page tables. This improper handling could result in inconsistencies and potential security issues.

Affected Version(s)

Xen consult Xen advisory XSA-486

References

https://xenbits.xenproject.org/xsa/advisory-486.html

CVSS V3.1

Score:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
High
Privileges Required:
Low
User Interaction:
None
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

This issue was discovered by Claude Opus 4.6 and diagnosed as a security issue by Rafal Wojtczuk.
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