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             AUSCERT External Security Bulletin Redistribution

 Buffer Overflow Vulnerability in Citrix ADC and Citrix NetScaler Gateway
                                14 May 2019


        AusCERT Security Bulletin Summary

Product:           Citrix ADC
                   Citrix NetScaler Gateway
Publisher:         Citrix
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2019-12044  

Original Bulletin: 

- --------------------------BEGIN INCLUDED TEXT--------------------

Buffer Overflow Vulnerability in Citrix ADC and Citrix NetScaler Gateway

Reference: CTX249976

Category : Medium

Created  : 13 May 2019

Modified : 13 May 2019

Applicable Products

  o Citrix ADC
  o NetScaler Gateway

Description of Problem

A buffer overflow vulnerability has been identified in Citrix ADC and Citrix
NetScaler Gateway which could possibly result in a denial-of-service in a
specific configuration.

This vulnerability has been assigned the following CVE number:

o CVE-2019-12044: Buffer overflow vulnerability in Citrix ADC and Citrix
NetScaler Gateway

This vulnerability is present in the following versions of Citrix ADC and
Citrix NetScaler Gateway:

10.5.x earlier than version 10.5.70

11.1.x earlier than version

12.0.x earlier than version

12.1.x earlier than version

Mitigating Factors

The vulnerability can be mitigated by ensuring that virtual servers stay in the
up state, or by disabling URL redirection. Removal of the redirect URL from the
load balancer configuration mitigates this issue. In situations where failover
is still needed for a down load balancer, ensure that the redirect URL contains
at least a domain name ending with a /.

How to Configure Redirect URL on NetScaler Virtual Server When Virtual Server
is Not Available- https://support.citrix.com/article/CTX108946

What Customers Should Do

This vulnerability has been addressed in new versions of the Citrix ADC and
Citrix NetScaler Gateway software. Citrix recommends that customers upgrade
their Citrix ADC and Citrix NetScaler Gateway appliances to one of the
following versions: and later and later and later

These upgrades can be obtained from the Citrix website at the following

Citrix ADC :


Citrix NetScaler Gateway:


The 10.5.70.x version is expected to release in the near future, until released
it is recommended to apply the configuration mitigation or upgrade to a fixed


|Date                           |Change                                       |
|13th May 2019                  |Initial publication                          |

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