Citrix NetScaler ADC and Citrix NetScaler Gateway Security Bulletin for CVE-2026

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

Article ID: CTX697096

Citrix NetScaler ADC and Citrix NetScaler Gateway are affected by the vulnerabilities identified below CVE-ID Description Pre-conditions CWE CVSSv4 CVE-2026-88771 A remote code execution vulnerability exists due to improper input validation, which can allow an unauthenticated attacker to execute arbitrary commands All NetScaler ADC and NetScaler Gateway deployments (Default configuration / No additional feature required) CWE-20: Improper Input Validation CVSS v4.0 Base Score: 9.5 (CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H) CVE-2026-88772 Memory overflow vulnerability leading to Remote Code Execution or Denial of Service DTLS configuration enabled on NetScaler ADC or NetScaler Gateway (Note: Enabled by default on VPN vServer) CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer CVSS v4.0 Base Score: 9.5 (CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H) CVE-2026-88773 HTTP Request Smuggling HTTP Configuration enabled on NetScaler ADC or NetScaler Gateway CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') CVSS v4.0 Base Score: 9.3 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N) CVE-2026-88774 Feature policy bypass due to improper HTTP URL based expression usage Any policy expression configured with HTTP URL based expression CWE-16: Configuration CVSS v4.0 Base Score:7 (CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N) CVE-2026-88775 Memory overflow vulnerability leading to unpredictable or erroneous behavior or Denial of Service NetScaler ADC or NetScaler Gateway configured as either:• Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy)• AAA virtual server CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer CVSS v4.0 Base Score: 8.8 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N) CVE-2026-88776 Memory overflow vulnerability leading to unpredictable or erroneous behavior or Denial of Service Configured as a Load Balancing (LB) virtual server of type Oracle on NetScaler ADC or NetScaler Gateway CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer CVSS v4.0 Base Score: 8.8 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N) CVE-2026-88777 Memory overflow vulnerability leading to unpredictable or erroneous behavior or Denial of Service Configured as an LB/CS or CGNAT-LSN/NAT64 device with a non-HTTP L7 protocol feature enabled on NetScaler ADC or NetScaler Gateway CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer CVSS v4.0 Base Score: 8.8 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N) CVE-2026-88778 TCP Initial Sequence Number (ISN) prediction TCP Configuration enabled on NetScaler ADC or NetScaler Gateway CWE-342: Predictable Exact Value from Values CVSS v4.0 Base Score: 8.8 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:H/SC:L/SI:L/SA:L) 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 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 add cs vserver add vpn vserver add authentication vserver 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 add cs vserver add vpn vserver add authentication vserver 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 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

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

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

add cs vserver

add vpn vserver

add authentication vserver

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

add cs vserver

add vpn vserver

add authentication vserver

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 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.

add (lb|cs) vserver .* FTP

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

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

set lsn group .* -rtspalg ENABLED

add lb vserver .* DNS .* -dns64 ENABLED

add dns policy64 # (must be bound to a DNS vserver to be vulnerable)

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"

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

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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.

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.

Additional Information

Cloud Software Group team has published a related blog at: which contains further context.

Citrix is notifying customers and channel partners this potential security issue through the publication of this security bulletin on the Citrix Knowledge Center at

Obtaining Support on This Issue

If you require technical assistance with this issue, please Citrix Technical Support. details for Citrix Technical Support are available at

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: