Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability

What happened

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

CISA lists it as exploited, added 27 Sep 2026.

NVD description

What to do

• Follow the vendor advisory for the fixed release and any interim mitigation.
  support.citrix.com
• Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
  cisa.gov

CISA’s notes for this entry:

• Running the provided IOCs in the NetScaler console may help identify indicators of exploitation. Customers must conduct forensic triage as directed by BOD 26‑04 and follow Citrix’s published guidance for mitigations. For more information, please see: community.citrix.com/techzone-blogs/110_security-updates/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve-2026-88771-through-cve-2026-88778
• support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697096
• support.citrix.com/external/article/CTX694799/steps-to-take-if-netscaler-adc-is-suspec.html
• BOD 26-04: cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
• Forensics Triage Requirements: cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
• nvd.nist.gov/vuln/detail/CVE-2026-88772