PT-2011-39: Denial of Service in Citrix XenServer Workload Balancer

Vulnerable software

Citrix XenServer Workload Balancer 
Version: and earlier

Application link:

Severity level

Severity level: High 
Impact: Denial of Service 
Access Vector: Network exploitable 

CVSS v2: 
Base Score: 7.8 
Vector: (AV:N/AC:L/Au:N/C:N/I:N/A:C)

CVE: not assigned


Vulnerability description

Positive Research Center has discovered a Denial of Service vulnerability in Citrix XenServer Workload Balancer.

Remote attackers can cause an unhandled exception in the DwmWebSvc component by sending a specially crafted HTTP request.

How to fix

Update your software up to the latest version

Advisory status

10.11.2011 - Vendor is notified
10.11.2011 - Vendor gets vulnerability details
13.03.2012 - Vendor releases fixed version and details
27.03.2012 - Public disclosure


The vulnerability was discovered by Kirill Mosolov, Positive Research Center (Positive Technologies Company)


Reports on the vulnerabilities previously discovered by Positive Research: