CVE-2023-46842

x86 HVM hypercalls may trigger Xen bug check

Published May 16, 2024 CVSS 3.1 · 6.5 Medium EPSS 8.5% KEV · Not listed
Description
Unlike 32-bit PV guests, HVM guests may switch freely between 64-bit and
other modes. This in particular means that they may set registers used
to pass 32-bit-mode hypercall arguments to values outside of the range
32-bit code would be able to set them to.

When processing of hypercalls takes a considerable amount of time,
the hypervisor may choose to invoke a hypercall continuation. Doing so
involves putting (perhaps updated) hypercall arguments in respective
registers. For guests not running in 64-bit mode this further involves
a certain amount of translation of the values.

Unfortunately internal sanity checking of these translated values
assumes high halves of registers to always be clear when invoking a
hypercall. When this is found not to be the case, it triggers a
consistency check in the hypervisor and causes a crash.

Analysis

No analysis available yet

Remediation

Vendor Workaround

Not using HVM / PVH guests will avoid the vulnerability.

Tracking

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Advisories

Source ID Title
Debian DSA Debian DSA DSA-5836-1 xen security update
History
Type Values Removed Values Added
First Time appeared Fedoraproject
Fedoraproject fedora
CPEs cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:40:*:*:*:*:*:*:*
cpe:2.3:o:xen:xen:*:*:*:*:*:*:x86:*
Vendors & Products Fedoraproject
Fedoraproject fedora
Type Values Removed Values Added
Weaknesses CWE-843
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H'}

ssvc

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

Weaknesses
  • CWE-843

    Access of Resource Using Incompatible Type ('Type Confusion')

Sources

Status
PUBLISHED
Assigner
XEN
Published
Updated
Nov 4, 2025, 5:12 PM
Reserved
Oct 27, 2023, 7:55 AM
Status
Analyzed
Published
May 16, 2024, 2:15 PM
Modified
Jun 17, 2026, 6:31 AM