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Fencer Vulns
medium 5.5

CVE-2023-34328 json

x86/AMD: Debug Mask handling

published 2024-01-05 2 y ago modified 2026-06-17 4 mo ago also EUVD-2023-38409

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.]

AMD CPUs since ~2014 have extensions to normal x86 debugging functionality. Xen supports guests using these extensions.

Unfortunately there are errors in Xen's handling of the guest state, leading to denials of service.

1) CVE-2023-34327 - An HVM vCPU can end up operating in the context of a previous vCPUs debug mask state.

2) CVE-2023-34328 - A PV vCPU can place a breakpoint over the live GDT. This allows the PV vCPU to exploit XSA-156 / CVE-2015-8104 and lock up the CPU entirely.

Patch / fix

  • xen xen 4.14.0
  • xen Debian 12 4.17.2+76-ge1f9cb16e2-1~deb12u1
  • xen Debian 14, Debian 13 4.17.2+55-g0b56bed864-1

debian advisories DEBIAN-CVE-2023-34328

  • xen SLE Module for Server Applications 15 SP4, SLE Module for Basesystem 15 SP4, SLE Micro 5.4 +4 more 4.16.5_08-150400.4.40.1
  • xen SLE Module for Server Applications 15 SP5, SLE Module for Basesystem 15 SP5, SLE Micro 5.5 +1 more 4.17.2_08-150500.3.15.1
  • xen SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 4.12.4_40-3.97.1
  • xen SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE Micro 5.2 +6 more 4.14.6_06-150300.3.57.1
  • xen SLE Module for Server Applications 15 SP4, SLE Module for Basesystem 15 SP4, SLE Micro 5.4 +2 more 4.16.5_06-150400.4.37.1
  • xen SLE Module for Server Applications 15 SP5, SLE Module for Basesystem 15 SP5, SLE Micro 5.5 +1 more 4.17.2_06-150500.3.12.1
  • xen SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLE High Performance Computing 15 SP1-LTSS 4.12.4_40-150100.3.95.1
  • xen SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE High Performance Computing 15 SP2-LTSS 4.13.5_06-150200.3.80.1

suse advisories SUSE-SU-2023:4476-1SUSE-SU-2023:4475-1SUSE-SU-2023:4185-1SUSE-SU-2023:4184-1SUSE-SU-2023:4183-1SUSE-SU-2023:4174-1

  • xen Alpine 3.15 4.15.5-r3
  • xen Alpine 3.17, Alpine 3.16 4.16.5-r3
  • xen Alpine 3.24, Alpine 3.23, Alpine 3.22 +4 more 4.17.2-r3

alpine advisories ALPINE-CVE-2023-34328

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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
18 mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Xen Xen

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.