+44 1865 950 828 Secure Your Business
Actively exploited

CVE-2026-88772 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

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch nowCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 27 Sep 2026.
  • Rated Critical severity (CVSS 9.5, scored by Vendor).
  • This product type is often exposed to the internet, which is where attackers scan for it first.
  • It has been in the catalogue for 40 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

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

Affected Versions

ProductVersions
Citrix NetScaler ADCbefore 14.1-73.37
before 13.1-64.23
before 14.1-73.37 FIPS
before 13.1.37.279 FIPS and NDcPP
Citrix NetScaler Gatewaybefore 14.1-73.37
before 13.1-64.23

From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Citrix NetScaler. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    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.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated critical, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 30 Sep 2026 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

Stay Ahead

More Exploited Citrix Flaws

Get alerts for CitrixWe email you when a new Citrix vulnerability is confirmed as exploited. Add more vendors on Threat Watch.

By signing up you agree to receive Threat Watch alerts. Unsubscribe at any time. See our Privacy Policy.

CVE-2026-88779Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer VulnerabilityAdded 4 Oct 2026CVE-2026-88771Citrix NetScaler Improper Input Validation VulnerabilityAdded 27 Sep 2026CVE-2026-19490Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel VulnerabilityAdded 9 Sep 2026CVE-2026-8452Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer VulnerabilityAdded 26 Aug 2026CVE-2026-3055Citrix NetScaler Out-of-Bounds Read VulnerabilityAdded 30 Mar 2026CVE-2025-7775Citrix NetScaler Memory Overflow VulnerabilityAdded 26 Aug 2025

All 27 exploited Citrix vulnerabilities

Not Sure If You Are Exposed?

Our attack surface and vulnerability teams can check your internet-facing estate for CVE-2026-88772 and every other exploited flaw on the list.

Check My Exposure
Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2026-88772
  3. CVE record: CVE-2026-88772
  4. FIRST EPSS
  5. support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697096
  6. support.citrix.com/external/article/CTX694799/steps-to-take-if-netscaler-adc-is-suspec.html
  7. support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697096&articleTitle=Citrix_NetScal