Citrix NetScaler ADC and Citrix NetScaler Gateway Security Bulletin for CVE-2026-88771, CVE-2026-88772, CVE-2026-88773, CVE-2026-88774, CVE-2026-88775, CVE-2026-88776, CVE-2026-88777, and CVE-2026-88778

by admin | Sep. 27, 2026 | ALARM, ctx_adc, ctx_workspace, WARNING

Article Id : CTX697096

Last Modified Date : 09-27-2026 15:25

Created Date : 09-27-2026 15:22

Article Record Type : Security BulletinSeverity :

 Critical

Summary

Severity – Critical

Description of Problem

Multiple vulnerabilities have been discovered in Citrix NetScaler ADC (formerly Citrix ADC) and Citrix NetScaler Gateway (formerly Citrix Gateway). Refer below for further details.

Affected Versions:

The following supported versions of Citrix NetScaler ADC and Citrix NetScaler Gateway are affected by the vulnerabilities:

• Citrix NetScaler ADC and Citrix NetScaler Gateway 14.1 BEFORE 14.1-73.37
• Citrix NetScaler ADC and Citrix NetScaler Gateway 13.1 BEFORE 13.1-64.23
• Citrix NetScaler ADC FIPS BEFORE 14.1-73.37 FIPS
• Citrix NetScaler ADC FIPS and NDcPP BEFORE 13.1-37.279

Additional Note: Secure Private Access Hybrid deployments using NetScaler instances are also affected by the vulnerabilities. Customers need to upgrade these NetScaler instances to the recommended NetScaler builds to address the vulnerabilities.

This bulletin only applies to customer-managed Citrix NetScaler ADC (“NetScaler ADC”) and Citrix NetScaler Gateway (“NetScaler Gateway”). Cloud Software Group upgrades the Citrix-managed cloud services and Citrix-managed Adaptive Authentication with the necessary software updates.

Disclaimer

The information on this page is being provided to you on an «AS IS» and «AS-AVAILABLE» basis. The issues described on this page may or may not impact your system(s). Cloud Software Group Holdings, Inc. and its affiliates, including Citrix Systems, Inc. (collectively, «Cloud SG») make no representations, warranties, or guarantees as to the information contained herein. ANY AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, WITHOUT LIMITATION, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY, NON-INFRINGEMENT AND FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. BY ACCESSING THIS PAGE, YOU ACKNOWLEDGE THAT CLOUD SG SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN. Cloud SG reserves the right to change or update the information on this page at any time. Cloud SG accordingly recommends that you always view the latest version of this page. The information contained herein is being provided to you under the terms of your applicable customer agreement with Cloud SG, and may be used only for the purposes contemplated by such agreement. If you do not have such an agreement with Cloud SG, this information is provided under the cloud.com Terms of Use, and may be used only for the purposes contemplated by such Terms of Use.

Details

Citrix NetScaler ADC and Citrix NetScaler Gateway are affected by the vulnerabilities identified below

What Customers Should Do

Exploits of CVE-2026-88771 and CVE-2026-88772 on unmitigated NetScaler deployments have been observed.

Cloud Software Group strongly urges affected customers of NetScaler ADC and NetScaler Gateway to install the relevant updated versions as soon as possible.

• Citrix NetScaler ADC and Citrix NetScaler Gateway 14.1-73.37 and later releases
• Citrix NetScaler ADC and Citrix NetScaler Gateway 13.1-64.23 and later releases of 13.1
• Citrix NetScaler ADC 14.1-FIPS 14.1-73.37 FIPS and later releases of 14.1-FIPS
• Citrix NetScaler ADC 13.1-FIPS and 13.1-NDcPP 13.1.37.279 and later releases of 13.1-FIPS and 13.1-NDcPP

NetScaler deployments impacted by CVE-2026-88778 should apply the TCP configuration change as mentioned in https://docs.netscaler.com/en-us/citrix-adc/current-release/system/tcp-configurations.html#enhanced-isn-generation

Steps to determine if an appliance meets the CVE preconditions

CVE-2026-88771
Precondition: All NetScaler ADC and NetScaler Gateway deployments (Default configuration / No additional feature required)

Instructions: All NetScaler ADC and NetScaler Gateway deployments are affected, including those deployed with the default configuration. No additional features or settings need to be enabled for the NetScaler deployment to be vulnerable.

CVE-2026-88772
Precondition: DTLS configuration enabled on NetScaler ADC or NetScaler Gateway (Note: Enabled by default on VPN vServer)

Instructions: Customers can determine whether their NetScaler deployment meets this precondition by inspecting the configuration for DTLS-enabled virtual servers. A NetScaler Gateway is vulnerable if DTLS is not explicitly disabled, and other virtual servers are vulnerable if they are configured with type DTLS.

Relevant configuration patterns to check:

• add vpn vserver vpn1 SSL 10.0.0.0 443 -Listenpolicy NONE 
  This indicates DTLS is not explicitly disabled, so DTLS is enabled by default.
• add vpn vserver vpn1 SSL 10.0.0.0 443 -dtls OFF -Listenpolicy NONE
  This indicates DTLS is explicitly disabled, so the precondition is not met.
• add vpn vserver vs1 DTLS 10.11.1.1 443
  This indicates DTLS is enabled.
• add lb vserver vd_dtls DTLS 10.146.111.74 443 -persistenceType NONE -cltTimeout 120
  This indicates DTLS is enabled.

CVE-2026-88773
Precondition: HTTP Configuration enabled on NetScaler ADC or NetScaler Gateway

Instructions: Customers can determine whether their NetScaler deployment meets this precondition if Load Balancing, Content Switching, VPN, or Authentication virtual servers of type HTTP or SSL are configured on NetScaler ADC or NetScaler Gateway.

• add lb vserver <vserver-name> <HTTP or SSL>
• add cs vserver <vserver-name> <HTTP or SSL>
• add vpn vserver <vserver-name> <HTTP or SSL>
• add authentication vserver <vserver-name> <HTTP or SSL>

CVE-2026-88774
Precondition: Any policy expression configured with HTTP URL based expression

Instructions: Customers can determine whether their NetScaler deployment meets this precondition if Load Balancing, Content Switching, VPN, or Authentication virtual servers of type HTTP or SSL are configured on NetScaler ADC or NetScaler Gateway.

• add lb vserver <vserver-name> <HTTP or SSL>
• add cs vserver <vserver-name> <HTTP or SSL>
• add vpn vserver <vserver-name> <HTTP or SSL>
• add authentication vserver <vserver-name> <HTTP or SSL>

CVE-2026-88775
Precondition: NetScaler ADC or NetScaler Gateway configured as either:

• Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy)
• AAA virtual server

Instructions: Customers can determine whether their NetScaler deployment meets the precondition by inspecting their NetScaler configuration for entries matching either of the following regular expressions:

• Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy):
  add vpn vserver .*
• AAA virtual server:
  add authentication vserver .*

CVE-2026-88776
Preconditions: Configured as a Load Balancing (LB) virtual server of type Oracle on NetScaler ADC or NetScaler Gateway

Instructions: Customers can determine whether their NetScaler deployment meets this precondition by inspecting their NetScaler configuration for entries matching the following regular expression:

• add lb vserver.*ORACLE.*

CVE-2026-88777
Preconditions: Configured as an LB/CS or CGNAT-LSN/NAT64 device with a non-HTTP L7 protocol feature enabled on NetScaler ADC or NetScaler Gateway

Instructions: Customers can determine whether their NetScaler deployment meets this precondition by inspecting their NetScaler configuration, such as /nsconfig/ns.conf or the output of show ns runningConfig, for entries matching any of the following case-insensitive regular-expression patterns. These patterns are intended for configuration-text search and are not NetScaler CLI commands.

• grep -iE '' /nsconfig/ns.conf

A match against any pattern below indicates that the precondition may be met. Text after # is explanatory and is not part of the pattern.

FTP over LB / CS:

• add (lb|cs) vserver .* FTP
• add service .* FTP

FTP over LSN/CGNAT — FTP ALG is enabled by default unless explicitly disabled:

• add lsn group .*
• set lsn group .* -ftp DISABLED # explicitly disabled; if this line is absent, FTP ALG is treated as enabled, and the appliance is vulnerable

FTP via non-HTTP health monitor

• add lb monitor .* FTP
• add lb monitor .* FTP-EXTENDED

RTSP over LSN/CGNAT

• set lsn group .* -rtspalg ENABLED

DNS64

• add lb vserver .* DNS .* -dns64 ENABLED
• add dns policy64 # (must be bound to a DNS vserver to be vulnerable)

NAT64

• add nat64

CVE-2026-88778
Preconditions: TCP Configuration enabled on NetScaler ADC or NetScaler Gateway

Instructions: Customers can determine whether their NetScaler deployment meets the precondition by verifying that both of the following conditions are true:

• At least one virtual server is configured with one of the following types: HTTP, SSL, SSL_BRIDGE, TCP, SSL_TCP, FTP, NNTP, RTSP, RDP, DNS_TCP, DOT, SIP_TCP, SIP_SSL, DIAMETER, SSL_DIAMETER, MYSQL, MSSQL, ORACLE, SMPP, MQTT, MQTT_TLS, MONGO, MONGO_TLS, PROXY, SSL_PROXY, USER_TCP, USER_SSL_TCP
  
  AND
• The following command returns: Enhanced ISN Generation: DISABLED:
  
  show ns tcpparam | grep "Enhanced ISN Generation"

Acknowledgement

We acknowledge Michael Tucker, Chew Keong Tan and Alex Bernier of the JPMorgan Chase XOR Team, and Maxim Suhanov for working with us to protect our customers

Additional information / Reference

What Citrix is Doing

Citrix is notifying customers and channel partners about this potential security issue through the publication of this security bulletin on the Citrix Knowledge Center at https://support.citrix.com/support-home/topic-article-list?trendingCategory=20&trendingTopicName=Security%20Bulletin  

Obtaining Support on This Issue

If you require technical assistance with this issue, please contact Citrix Technical Support. Contact details for Citrix Technical Support are available at https://support.citrix.com/support-home/home 

Subscribe to Receive Alerts

Citrix strongly recommends that all customers subscribe to receive alerts when a Citrix security bulletin is created or modified at https://support.citrix.com/wolken-support/view/aboutsupport/my-support-alerts  

Reporting Security Vulnerabilities to Citrix

Citrix welcomes input regarding the security of its products and considers any and all potential vulnerabilities seriously. For details on our vulnerability response process and guidance on how to report security-related issues to Citrix, please see the following webpage: https://www.cloud.com/trust-center/support 

NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-2026-8451, CVE-2026-8452, CVE-2026-8655, CVE-2026-10816, CVE-2026-10817, and CVE-2026-13474

by admin | Juni 30, 2026 | ALARM, ctx_adc, ctx_workspace, WARNING

Article Id : CTX696604

Last Modified Date : 06-30-2026 13:30

Created Date : 06-30-2026 13:30

Article Record Type : Security BulletinSeverity :

 High

Summary

Severity – High

Description of Problem

Multiple vulnerabilities have been discovered in NetScaler ADC (formerly Citrix ADC) and NetScaler Gateway (formerly Citrix Gateway). Refer below for further details.

Affected Versions:

The following supported versions of NetScaler ADC and NetScaler Gateway are affected by the vulnerabilities: 

• NetScaler ADC and NetScaler Gateway 14.1 BEFORE 14.1-72.61
• NetScaler ADC and NetScaler Gateway 13.1 BEFORE 13.1-63.18
• NetScaler ADC FIPS BEFORE 14.1-72.61 FIPS
• NetScaler ADC FIPS and NDcPP BEFORE 13.1-37.272

Note: Secure Private Access Hybrid deployments using NetScaler instances are also affected by the vulnerabilities. Customers need to upgrade these NetScaler instances to the recommended NetScaler builds to address the vulnerabilities. 

This bulletin only applies to customer-managed NetScaler ADC and NetScaler Gateway. Cloud Software Group upgrades the Citrix-managed cloud services and Citrix-managed Adaptive Authentication with the necessary software updates.

Disclaimer

The information on this page is being provided to you on an «AS IS» and «AS-AVAILABLE» basis. The issues described on this page may or may not impact your system(s). Cloud Software Group, Inc. and its subsidiaries (collectively, «Cloud SG») make no representations, warranties, or guarantees as to the information contained herein. ANY AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, WITHOUT LIMITATION, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY, NON-INFRINGEMENT AND FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. BY ACCESSING THIS PAGE, YOU ACKNOWLEDGE THAT CLOUD SG SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN. Cloud SG reserves the right to change or update the information on this page at any time. We accordingly recommend that you always view the latest version of this page. The information contained herein is being provided to you under the terms of your applicable customer agreement with Cloud SG, and may be used only for the purposes contemplated by such agreement. If you do not have such an agreement with Cloud SG, this information is provided under the cloud.com Terms of Use, and may be used only for the purposes contemplated by such Terms of Use.

Details

NetScaler ADC and NetScaler Gateway are affected by the vulnerabilities mentioned below:

What Customers Should Do

Cloud Software Group strongly urges affected customers of NetScaler ADC and NetScaler Gateway to install the relevant updated versions as soon as possible. 

• NetScaler ADC and NetScaler Gateway 14.1-72.61 and later releases
• NetScaler ADC and NetScaler Gateway 13.1-63.18 and later releases of 13.1
• NetScaler ADC 14.1-FIPS 14.1-72.61 FIPS and later releases of 14.1-FIPS
• NetScaler ADC 13.1-FIPS and 13.1-NDcPP 13.1.37.272 and later releases of 13.1-FIPS and 13.1-NDcPP

CVE-2026-13474

Customers must upgrade to the above-mentioned NetScaler firmware versions that include the fix and update their configuration as described below. 
Configure the Http2SmallWndTimeout parameter, which controls the timeout (in seconds) for HTTP/2 small‑window stalled streams.

• For appliances using HTTP Strict Profiles, this parameter defaults to 30 seconds, and the fix is effective immediately after the upgrade.
• For appliances NOT using HTTP Strict Profiles, the default value is 0, and in that case, merely upgrading to the builds containing the fix WILL NOT address the vulnerability completely. In this case, customers must manually set Http2SmallWndTimeout to 30 seconds.

Please note that Http2SmallWndTimeout is a new parameter and is only available in the firmware builds that contain the fix.

Configuration command: 

set ns httpProfile <profile_name> -http2SmallWndTimeout <value_in_seconds> 

Steps to determine if an appliance meets the CVE preconditions

CVE-2026-8451: 

Customers can determine if the appliance meets the precondition by inspecting their NetScaler configuration for the specified string:

• add authentication samlIdPProfile .*

CVE-2026-8452 :  

Customers can determine if the appliance meets the precondition by inspecting their NetScaler configuration for the specified string:

• An Auth Server (AAA Vserver):
  • add authentication vserver .*
• A Gateway (VPN Vserver,  ICA Proxy, CVPN, RDP Proxy) :
  • add vpn vserver .*

CVE-2026-8655 :

Customers can determine if the appliance meets the precondition by inspecting their NetScaler configuration for the specified string:

• An LB or CS vserver of type Oracle(LB Vserver):
  • add lb vserver.*ORACLE.*
• A CS or LB vserver of type DNS,DNS_TCP,  DOT or SSL with DNSoverHTTPS enabled :
  • add cs vserver.*DNS.*
  • add lb vserver.*DNS.*
  • add cs vserver.*DOT.*
  • add lb vserver.*DOT.*
  • add cs vserver.*SSL.*dnsOverHttps.*
  • add lb vserver.*SSL.*dnsOverHttps.*    
• DNS global parameter or dns profile with recursive resolution enabled:
  • set dns parameter.*-recursion ENABLED.*
  • add dns profile.*recursiveResolution ENABLED

CVE-2026-10817:  

Customers can determine if the appliance meets the precondition by inspecting their NetScaler configuration for the specified string:

• Search for “TimeStamp ENABLED” to identify all TCP profiles that have the TimeStamp option enabled.     
• Then search for the identified TCP profile name to determine which vservers and services it is attached to.        

       Note: If TimeStamp is enabled on nstcp_default_profile, then all vservers and services that do not have an explicit TCP profile attached will be impacted, as they inherit nstcp_default_profile by default.
   
        Example:
        add ns tcpProfile custom_profile -TimeStamp ENABLED
        add lb vserver test_server HTTP 10.10.10.20 80 -persistenceType NONE -cltTimeout 180 -tcpProfileName custom_profile
        add service s1 20.20.20.2 HTTP 80 -gslb NONE -maxClient 0 -maxReq 0 -cip DISABLED -usip NO -useproxyport YES -sp OFF -cltTimeout 180 -svrTimeout 360 -CKA NO -TCPB NO -CMP NO -tcpProfileName custom_profile

CVE-2026-13474:  

Customers can determine if the appliance meets the precondition by inspecting their NetScaler configuration for the specified string:

• Profile Check: Identify if -http2 ENABLED is set on any HTTP profile. If none are found, the appliance is considered non-vulnerable.
• vServer Association: If such a profile exists, identify all LB, CS, and VPN vServers that reference it.
• Default Profile Handling: If default profile nshttp_default_profile has -http2 enabled, identify all vServers that utilize this default profile. (i.e., those without an explicit -httpProfileName assignment).