Kernel Task Isolation Flaw in Xen Hypervisor by Xen Project
CVE-2026-23553

2.9LOW

Key Information:

Vendor

Xen Project
Status
Xen Project
Vendor
CVE Published:
28 January 2026

What is CVE-2026-23553?

A vulnerability exists within the Xen Hypervisor's context switch logic, specifically related to Instruction Buffer Prediction (IBPB) mechanisms between virtual CPUs (vCPUs). When a vCPU moves between CPUs, Xen erroneously skips IBPB, compromising the guest kernel's ability to effectively isolate tasks within its environment. This flaw allows task data from one vCPU to potentially persist on another, endangering data confidentiality and integrity during context switches.

Affected Version(s)

Xen consult Xen advisory XSA-479

References

https://xenbits.xenproject.org/xsa/advisory-479.html

CVSS V3.1

Score:
2.9
Severity:
LOW
Confidentiality:
Low
Integrity:
None
Availability:
Low
Attack Vector:
Local
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

This issue was discovered by David Kaplan of AMD.
.