HVM guest I/O port accesses are subject to either emulation or at least
translation. Translations are managed by the device model (via
XEN_DOMCTL_ioport_mapping), and hence the linked list used may changed
at any time. Traversal of those lists (while handling guest I/O port
accesses) therefore needs synchronizing with updates, which was missing
so far.

Project Subscriptions

Vendors Products
Advisories
Source ID Title
Debian DSA Debian DSA DSA-6424-1 xen security update
Fixes

Solution

No solution given by the vendor.


Workaround

Running only PV or PVH guests will avoid the vulnerability. (Switching from a device model stub domain or a de-privileged device model to a fully privileged Dom0 device model does NOT mitigate this vulnerability. Rather, it simply recategorises the vulnerability to hostile management code, regarding it "as designed"; thus it merely reclassifies these issues as "not a bug". The security of a Xen system using stub domains is still better than with a qemu-dm running as a Dom0 process. Users and vendors of stub qemu dm systems should not change their configuration to use a Dom0 qemu process.)

History

Thu, 18 Jun 2026 21:15:00 +0000

Type Values Removed Values Added
First Time appeared Xen
Xen xen
Vendors & Products Xen
Xen xen

Thu, 18 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
Description HVM guest I/O port accesses are subject to either emulation or at least translation. Translations are managed by the device model (via XEN_DOMCTL_ioport_mapping), and hence the linked list used may changed at any time. Traversal of those lists (while handling guest I/O port accesses) therefore needs synchronizing with updates, which was missing so far.
Title x86 HVM I/O port list traversal
Weaknesses CWE-362
References
Metrics cvssV3_1

{'score': 7.9, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: XEN

Published:

Updated: 2026-06-18T15:07:31.335Z

Reserved: 2026-04-27T14:20:24.138Z

Link: CVE-2026-42487

cve-icon Vulnrichment

Updated: 2026-06-18T15:07:31.335Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-18T21:00:13Z

Weaknesses