Multiple vulnerabilities have been discovered in Citrix ADC (formerly known as NetScaler ADC), Citrix Gateway (formerly known as NetScaler Gateway), and Citrix SD-WAN WANOP Edition appliance models 4000-WO, 4100-WO, 5000-WO, and 5100-WO. These vulnerabilities, if exploited, could result in the following security issues:
 

CVE-ID	Description	CWE	Affected Products	Pre-conditions
CVE-2020-8299	Network-based denial-of-service from within the same Layer 2 network segment	CWE-400: Uncontrolled Resource Consumption	Citrix ADC, Citrix Gateway, Citrix SD-WAN WANOP Edition	The attacker machine must be in the same Layer 2 network segment as the vulnerable appliance
CVE-2020-8300	SAML authentication hijack through a phishing attack to steal a valid user session	CWE-284: Improper access control	Citrix ADC, Citrix Gateway	Citrix ADC or Citrix Gateway must be configured as a SAML SP or a SAML IdP

The following supported versions of Citrix ADC, Citrix Gateway, and Citrix SD-WAN WANOP Edition are affected by CVE-2020-8299:
 

• Citrix ADC and Citrix Gateway 13.0 before 13.0-76.29
• Citrix ADC and Citrix Gateway 12.1 before 12.1-61.18
• Citrix ADC and NetScaler Gateway 11.1 before 65.20
• Citrix ADC 12.1-FIPS before 12.1-55.238
• Citrix SD-WAN WANOP Edition 11.4 before 11.4.0
• Citrix SD-WAN WANOP Edition 11.3 before 11.3.2
• Citrix SD-WAN WANOP Edition 11.3 before 11.3.1a
• Citrix SD-WAN WANOP Edition 11.2 before 11.2.3a
• Citrix SD-WAN WANOP Edition 11.1 before 11.1.2c
• Citrix SD-WAN WANOP Edition 10.2 before 10.2.9a

The following supported versions of Citrix ADC and Citrix Gateway are affected by CVE-2020-8300:

• Citrix ADC and Citrix Gateway 13.0. before 13.0-82.41
• Citrix ADC and Citrix Gateway 12.1 before 12.1-62.23
• Citrix ADC and NetScaler Gateway 11.1 before 11.1-65.20
• Citrix ADC 12.1-FIPS before 12.1-55.238

These issues have already been addressed in Citrix-managed cloud services such as Citrix Gateway Service and Citrix Secure Workspace Access. Customers using Citrix-managed services do not need to take any additional action.

---

Instructions

The following supported versions of Citrix ADC, Citrix Gateway, and Citrix SD-WAN WANOP Edition address CVE-2020-8299, a Medium severity vulnerability.  

• Citrix ADC and Citrix Gateway 13.0-76.29 and later releases of 13.0 

• Citrix ADC and Citrix Gateway 12.1-61.18 and later releases of 12.1 

• Citrix ADC and NetScaler Gateway 11.1-65.20 and later releases of 11.1 

• Citrix ADC 12.1-FIPS 12.1-55.238 and later releases of 12.1-FIPS 

• Citrix SD-WAN WANOP Edition 11.4.0 and later releases of 11.4 

• Citrix SD-WAN WANOP Edition 11.3.2 and later releases of 11.3 

• Citrix SD-WAN WANOP Edition 11.3.1a and later releases of 11.3 

• Citrix SD-WAN WANOP Edition 11.2.3a and later releases of 11.2 

• Citrix SD-WAN WANOP Edition 11.1.2c and later releases of 11.1 

• Citrix SD-WAN WANOP Edition 10.2.9a and later releases of 10.2 

The following supported versions of Citrix ADC and Citrix Gateway address CVE-2020-8300, a High severity vulnerability.  

• Citrix ADC and Citrix Gateway 13.0-82.41* and later releases of 13.0 

• Citrix ADC and NetScaler Gateway ADC 12.1-62.23* and later releases of 12.1 

• Citrix ADC and NetScaler Gateway 11.1-65.20 and later releases of 11.1 

• Citrix ADC 12.1-FIPS 12.1-55.238 and later releases of 12.1-FIPS 
   

In addition, upon upgrading to the fixed version, customers must modify the device configuration to resolve CVE-2020-8300. See Citrix Application Delivery Controller and Citrix Gateway - SAML Configuration Reference Guide for details. 
 

*Update:

Citrix is aware of a functionality issue in the recently released firmware relating to Citrix Gateway’s integration with Citrix Workspace App. 

Customers who have upgraded and are not experiencing any functionality issues logging into Citrix Workspace App do not need to take any additional actions.  

Customers who are using 13.0-82.41 and 12.1-62.23 versions and are experiencing functionality issues logging into Citrix Workspace App are recommended to upgrade to the following versions: 

• Citrix ADC and Citrix Gateway 13.0-82.42 and later releases of 13.0 

• Citrix ADC and NetScaler Gateway ADC 12.1-62.25 and later releases of 12.1 

Citrix strongly recommends that affected customers install relevant updates as soon as possible. 

---

Acknowledgements

Citrix would like to thank ChenNan of Chaitin Security Research Lab, Wolfgang Ettlinger and Marc Nimmerrichter of Certitude Consulting for working with us to protect Citrix customers.

Date	Change
2021-06-08	Initial Publication
2021-06-08	Formatting Corrections
2021-06-11	Citrix Workspace App Functionality Issue – Builds Updated