Citrix XenServer Multiple Vulnerabilities (CTX216071)

medium Nessus Plugin ID 93608
New! Plugin Severity Now Using CVSS v3

The calculated severity for Plugins has been updated to use CVSS v3 by default. Plugins that do not have a CVSS v3 score will fall back to CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.


The remote host is affected by multiple vulnerabilities.


The version of Citrix XenServer running on the remote host is missing a security hotfix. It is, therefore, affected by multiple vulnerabilities :

- A flaw exists due to improper handling of pagetable walks that contain recursive L3 pagetable entries. An attacker on the guest can exploit this to gain elevated privileges. (CVE-2016-7092)

- A flaw exists due to improper handling of instruction pointer truncation when emulating HVM instructions. An attacker on the guest can exploit this to gain elevated privileges. (CVE-2016-7093)

- An overflow condition exists in the x86 HVM guests due to improper handling of writing to pagetables, specifically when the guest is running shadow paging using a subset of the x86 emulator. An attacker on the guest can exploit this to cause a denial of service condition on the host. (CVE-2016-7094)

- A use-after-free error exists when calling the EVTCHNOP_init_control operation with a bad guest frame number. An attacker on the guest can exploit this, by freeing a control structure without also clearing the corresponding pointer, to crash the host or potentially gain elevated privileges. (CVE-2016-7154)


Apply the appropriate hotfix according to the vendor advisory.

See Also

Plugin Details

Severity: Medium

ID: 93608

File Name: citrix_xenserver_CTX216071.nasl

Version: 1.12

Type: local

Family: Misc.

Published: 9/20/2016

Updated: 11/14/2019

Dependencies: citrix_xenserver_version.nbin

Risk Information

CVSS Score Source: CVE-2016-7154


Risk Factor: Medium

Score: 6.7


Risk Factor: High

Base Score: 7.2

Temporal Score: 5.3

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

Temporal Vector: E:U/RL:OF/RC:C


Risk Factor: Medium

Base Score: 6.7

Temporal Score: 5.8

Vector: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:citrix:xenserver

Required KB Items: Host/XenServer/version, Host/local_checks_enabled

Exploit Ease: No known exploits are available

Patch Publication Date: 9/8/2016

Vulnerability Publication Date: 9/8/2016

Reference Information

CVE: CVE-2016-7092, CVE-2016-7093, CVE-2016-7094, CVE-2016-7154

BID: 92862, 92863, 92864, 92865