Improper Input Validation Affecting xen package, versions <4.11.3+24-g14b62ab3e5-1


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.56% (79th percentile)

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  • Snyk IDSNYK-DEBIAN11-XEN-537570
  • published11 Dec 2019
  • disclosed11 Dec 2019

Introduced: 11 Dec 2019

CVE-2019-19583  (opens in a new tab)
CWE-20  (opens in a new tab)

How to fix?

Upgrade Debian:11 xen to version 4.11.3+24-g14b62ab3e5-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream xen package and not the xen package as distributed by Debian. See How to fix? for Debian:11 relevant fixed versions and status.

An issue was discovered in Xen through 4.12.x allowing x86 HVM/PVH guest OS users to cause a denial of service (guest OS crash) because VMX VMEntry checks mishandle a certain case. Please see XSA-260 for background on the MovSS shadow. Please see XSA-156 for background on the need for #DB interception. The VMX VMEntry checks do not like the exact combination of state which occurs when #DB in intercepted, Single Stepping is active, and blocked by STI/MovSS is active, despite this being a legitimate state to be in. The resulting VMEntry failure is fatal to the guest. HVM/PVH guest userspace code may be able to crash the guest, resulting in a guest Denial of Service. All versions of Xen are affected. Only systems supporting VMX hardware virtual extensions (Intel, Cyrix, or Zhaoxin CPUs) are affected. Arm and AMD systems are unaffected. Only HVM/PVH guests are affected. PV guests cannot leverage the vulnerability.

CVSS Scores

version 3.1