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Fencer Vulns
medium 6.5

CVE-2023-46842 json

x86 HVM hypercalls may trigger Xen bug check

published 2024-05-16 2 y ago modified 2026-06-17 4 mo ago also EUVD-2023-51008

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
8.5%
EPSS 8.5% chance of exploitation in 30 days, percentile 95%
public exploits
0
none known

Summary

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.

Patch / fix

  • xen Debian 12 4.17.5+23-ga4e5191dc0-1
  • xen Debian 14, Debian 13 4.19.1-1

debian advisories DEBIAN-CVE-2023-46842

  • xen SLE Module for Server Applications 15 SP5, SLE Module for Basesystem 15 SP5, SLE Micro 5.5 +2 more 4.17.4_04-150500.3.33.1
  • xen SLE Module for Server Applications 15 SP6, SLE Module for Basesystem 15 SP6, openSUSE Leap 15.6 4.18.2_06-150600.3.3.1
  • xen SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 4.12.4_48-3.109.1
  • xen SLE Micro 5.2, SLE Micro 5.1 4.14.6_14-150300.3.72.1
  • xen SLE Module for Server Applications 15 SP5, SLE Module for Basesystem 15 SP5, SLE Micro 5.5 +1 more 4.17.4_02-150500.3.30.1
  • xen SLE Micro 5.4, SLE Micro 5.3, openSUSE Leap Micro 5.4 +1 more 4.16.6_02-150400.4.55.1
  • xen SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE High Performance Computing 15 SP2-LTSS 4.13.5_12-150200.3.93.1

suse advisories SUSE-SU-2024:2654-1SUSE-SU-2024:2535-1SUSE-SU-2024:2531-1SUSE-SU-2024:1541-1SUSE-SU-2024:1540-1SUSE-SU-2024:1295-1

  • xen openSUSE Tumbleweed 4.18.2_02-1.1

opensuse advisories openSUSE-SU-2024:13853-1

  • xen Alpine 3.17, Alpine 3.16 4.16.6-r0
  • xen Alpine 3.18 4.17.4-r0
  • xen Alpine 3.24, Alpine 3.23, Alpine 3.22 +3 more 4.18.2-r0

alpine advisories ALPINE-CVE-2023-46842

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-46842 updated cvss 5.1

xen: x86 HVM hypercalls may trigger Xen bug check

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

8.53% chance of exploitation in the next 30 days, higher than 95% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
CNA 3.1 6.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Affected products

  • Xen Xen

Classification

Weakness
  • CWE-843 Access of Resource Using Incompatible Type

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.