CVE-2023-34328 x86/AMD: Debug Mask handling

2024-01-0516:34:11

XEN

www.cve.org

amd

x86

debugging

xen

vulnerabilities

denial of service

6.2 Medium

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

42.2%

JSON

[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.

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

CNA Affected

[
  {
    "defaultStatus": "unknown",
    "product": "Xen",
    "vendor": "Xen",
    "versions": [
      {
        "status": "unknown",
        "version": "consult Xen advisory XSA-444"
      }
    ]
  }
]