Citrix Hypervisor Security Update

2021-09-0710:10:42

support.citrix.com

7.8 High

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

4.9 Medium

CVSS2

Access Vector

LOCAL

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

COMPLETE

AV:L/AC:L/Au:N/C:N/I:N/A:C

0.001 Low

EPSS

Percentile

49.6%

JSON

Several security issues have been discovered in Citrix Hypervisor that, collectively, may allow privileged code in a guest VM to compromise or crash the host.
These issues have the following identifiers:

CVE-ID	Description	Pre-requisites
CVE-2021-28694	Host denial of service	Malicious privileged code execution in a guest VM running on a host with firmware that declares ACPI tables which includes memory regions that are identity mapped for devices that have been explicitly assigned, by the host administrator, to that guest VM in PCI passthrough mode.
CVE-2021-28697	Host compromise	Malicious privileged code execution in a guest VM that has two or more vCPUs allocated to it
CVE-2021-28698	Host denial of service	Malicious privileged code execution in a guest VM
CVE-2021-28699	Host compromise	Malicious privileged code execution in a guest VM on a host where the host administrator has modified the guest or host grant table limits
CVE-2021-28701	Host compromise	Malicious privileged code execution in a guest VM that has two or more vCPUs allocated to it

All currently supported versions of Citrix Hypervisor are affected by all of these issues with the exception of CVE-2021-28699 which only affects Citrix Hypervisor 8.2 LTSR.