Xen Hypervisor Flaws Let One Malicious VM Read and Write Any Other VM's Memory

[Starburst-David]

Two flaws in the Xen hypervisor allow a malicious guest virtual machine (VM) to read and write the memory of other VMs on the same host, including dom0.

Dom0 is the VM that, by default, has full permissions and manages the others. Patches are out, and there is no known mitigation, the Xen Project said in an advisory on November 3.

All Xen versions from 4.6 onward are vulnerable, while 4.5 and earlier are not. The flaws are tracked as CVE-2026-102703 and CVE-2026-102704, under Xen advisory XSA-523.

The Xen Project credited AI company Anthropic with finding the flaws using its Claude model. Stephan Lipp of Ada Logics then validated the finding, and the CodeAnt AI Security Research Team later independently reported the same issue.

The flaws are in grant copy, the operation Xen uses to copy data between VMs. Each VM tells Xen which of its memory pages other VMs may use, and Xen checks those permissions.

Full article at:
https://thehackernews.com/2026/11/xen-h ... cious.html

Published Date: Nov 04, 2026

Vulnerabilities has been mentioned in this article:
CVE-2026-102704 CVE-2026-102703