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

Citrix NetScaler ADC and NetScaler Gateway contain an improper restriction of operations within the bounds of a memory buffer vulnerability that could allow for remote code execution or denial of service

Why it matters

• This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, which means it has been observed being exploited in the wild.

Affected

• Vendor: Citrix
• Product: NetScaler
• Identifier: CVE-2026-88772
• FlawFind severity: high
• Weakness: CWE-119

What to do

• 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.
• U.S. federal remediation deadline: 2026-09-30
• Inventory the affected product, prioritise internet-facing instances, and patch or mitigate immediately.
• Audit your own systems for the same weakness class — FlawFind can test your applications and APIs for it and prove what is exploitable.

Notes

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: https://community.citrix.com/techzone-blogs/110_security-updates/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve-2026-88771-through-cve-2026-88778 ; https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697096 ; https://support.citrix.com/external/article/CTX694799/steps-to-take-if-netscaler-adc-is-suspec.html ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-88772