VSA-2026-010: Floating Point Divider State Sampling on AMD CPUs
| Published | Updated | Severity | CVSS 4.0 | Affected products |
|---|---|---|---|---|
| 2026-04-28 | 2026-04-28 | 🟠Moderate | 2.0 | - XCP-ng 8.3 |
A vulnerability on the Xen hypervisor has been discovered. For Vates products, we classify the impact as Medium, as impact is limited or requires unusual conditions. For details on how we assign severity levels, see our Severity Levels Explained page.
Summary​
The Xen project recently disclosed a vulnerability affecting all previous versions of the Xen hypervisor.
Researchers from CISPA reported "Floating Point Divider State Sampling (FP-DSS)", a transient execution vulnerability, affecting multiple generations of AMD CPUs. AMD assesses that potential information-leakage risk in real-world deployments appears limited due to the constrained nature of the data involved and the relatively uncommon use of floating-point operations in privileged code.
Impact​
An attacker might be able to infer data belonging to other contexts, including data belonging to other guests.
Affected Versions​
Systems running XCP-ng 8.3 LTS on AMD Fam17h CPUs (Zen1 micro-architecture) are believed to be vulnerable. Other AMD CPUs and CPUs from other manufacturers are not known to be affected.
- XCP-ng 8.3:
xen-4.13.4-10.27.xcpng8.3and later are affected.
Mitigation​
There are no known mitigation.
Resolution​
As of the 2026-04-28, the updated xen-* packages for XCP-ng 8.3 have been updated to address this issue.
List of packages fixing this issue:
- XCP-ng 8.3:
xen-4.17.6-6.2.xcpng8.3
Credits​
This issue was reported by Researchers from the CISPA Helmholtz Center for Information Security (Daniel Weber, Fabian Schwarz, Leon Trampert, Ruiyi Zhang, Michael Schwarz), and fixed by Andrew Cooper of Citrix.