# Xen patches flaws that let guest machines access other virtual machines' memory

_Published Wednesday, November 4, 2026 at 8:42 AM EST · Security, Infrastructure · Latest · Tier 2 — Notable_

![Xen patches flaws that let guest machines access other virtual machines' memory — Primary](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAVPXiuTBfhBnpwaZHMfSDWymKJrXbS88kOEO1Xuh5t11qAnwSKeFTHGQy6ZG9Sr2N-wRYrJg58x3lKFbybvU9p1a85lxaCHfBa61vO1DfjEhUi5Yzf6bQS1eN7Mu-s_sUwkE-JGc-UznJ1p0qfmwMDusXFzWawXKXMt6jj-vENxyQG12uAUDUe0p0gtg/s1700-nu-rw-lo-l85-e365/xen.jpg)

The Xen Project disclosed two flaws on November 3 that let a malicious guest virtual machine read and write other virtual machines' memory, including the management machine that normally controls the host. Xen versions 4.6 onward are affected, and patches are available.

The flaws arise when Xen improperly reuses permission checks while copying data between virtual machines. XCP-ng 8.3 has released a fix requiring a host reboot. Qubes OS 4.3 fixes entered security testing, with stable distribution due over the next two weeks. Xen lists no known mitigation, and its advisory provides no patches for versions 4.6 through 4.16.

## Sources

- [The Hacker News](https://thehackernews.com/2026/11/xen-hypervisor-flaws-let-one-malicious.html)

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Canonical: https://techandbusiness.org/newswire/3LKQH-CcG6khl3E25OQZK0
Published: 2026-11-04T13:42:48.334Z
Story chronology: 2026-11-03T00:00:00.000Z
Retrieved: 2026-11-04T22:02:03.261Z
Publisher: Tech & Business (techandbusiness.org)