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CVE-2026-88772: Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability

CVE-2026-88772 is rated critical with a CVSS v4.0 base score of 9.5 and affects Citrix NetScaler. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-09-27, which means exploitation in the wild has been observed.

Vulnerability description

Vulnerability in Citrix NetScaler ADC and Citrix NetScaler Gateway. This issue affects ADC: before 14.1-73.37, before 13.1-64.23, before 14.1-73.37 FIPS, and before 13.1.37.279 FIPS and NDcPP; Gateway: before 14.1-73.37 and before 13.1-64.23 leading to Remote Code Execution or Denial of Service

Severity breakdown

CVSS v4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

• Attack vector: Network. Exploitable remotely over the network.
• Attack complexity: High. Success depends on conditions or defences that must be bypassed.
• Attack requirements: None. No deployment or execution conditions are needed.
• Privileges required: None. No account or prior access is needed.
• User interaction: None. No action from any user is needed.
• Confidentiality impact (vulnerable system): High. Total loss of confidentiality.
• Integrity impact (vulnerable system): High. Total loss of integrity.
• Availability impact (vulnerable system): High. Total loss of availability.
• Confidentiality impact (subsequent systems): High. Total loss of confidentiality on other systems.
• Integrity impact (subsequent systems): High. Total loss of integrity on other systems.
• Availability impact (subsequent systems): High. Total loss of availability of other systems.

Underlying weakness

CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.

Affected products

• Citrix Netscaler Application Delivery Controller: from 13.1 before 13.1-64.23; from 13.1 before 13.1.37.279; from 14.1 before 14.1-73.37; from 14.1-66.68 up to and including 14.1-73.37
• Citrix Netscaler Gateway: from 13.1 before 13.1-64.23; from 14.1 before 14.1-73.37

References

• https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697096&articleTitle=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
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-88772