Citrix NetScaler Improper Input Validation Vulnerability

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• cpe citrix/netscaler application delivery controllerversion unspecified
• cpe citrix/netscaler gatewayversion unspecified
• vendor Citrix NetScalerversion unspecified
• vendor Citrix NetScaler ADC and NetScaler Gatewayversion unspecified

How to fix CVE-2026-88771

• Recommended remediation

  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 due date Sep 30, 2026.

• Official advisories

  • Canadian Centre for Cyber Security · cyber.gc.ca
  • CISA KEV · cisa.gov
  • CVE.org · cve.org
  • FIRST EPSS · first.org
  • Google Threat Intelligence · cloud.google.com
  • NIST NVD · nvd.nist.gov

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

1. Sep 27, 2026 · Catalog

   Detected

   Improper input validation 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 an unauthenticated attacker to execute arbitrary commands.

2. Sep 27, 2026 · CISA KEV

   Known exploited

   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

3. Sep 28, 2026 · Catalog

   Updated

   Improper input validation 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 an unauthenticated attacker to execute arbitrary commands.

4. Sep 30, 2026 · CISA KEV

   Remediation due

   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

Sources

• Canadian Centre for Cyber SecurityGovernment advisoryCVE-2026-88771

  Number: AL26-024 Date: September 27, 2026 Update: October 9, 2026 Audience This Alert is intended for IT professionals and managers. Purpose An Alert is used to raise awareness of a recently identified cyber threat that may impact cyber information assets, and to provide addition

  cyber.gc.ca
• CISA KEVConfirmed exploitationCVE-2026-88771

  Citrix NetScaler ADC and NetScaler Gateway contain an improper input validation vulnerability that could allow an unauthenticated attacker to execute arbitrary commands.

  cisa.gov
• CVE.orgVulnerability recordCVE-2026-88771

  Official CVE identifier

  cve.org
• FIRST EPSSExploitation probabilityCVE-2026-88771

  30-day exploitation probability 1.1%

  first.org
• Google Threat IntelligenceThreat researchCVE-2026-88771

  Research mention from Google Threat Intelligence. Not confirmation of exploitation.

  cloud.google.com
• NIST NVDVulnerability recordCVE-2026-88771

  Improper input validation 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

  nvd.nist.gov
• Rapid7 Vulnerability DatabaseResearchCVE-2026-88771

  Overview On September 27, 2026, Citrix disclosed eight new vulnerabilities affecting NetScaler ADC and NetScaler Gateway, including two critical remote code execution (RCE) vulnerabilities: CVE-2026-88771 and CVE-2026-88772 . Both of these RCE vulnerabilities carry a critical CVSSv4 score of 9.5, and both have been confirmed as being actively exploited in the wild as zero-days prior to the vendor

  rapid7.com
• Palo Alto Unit 42Threat researchCVE-2026-88771

  Research mention from Palo Alto Unit 42. Not confirmation of exploitation.

  unit42.paloaltonetworks.com
• VulnCheck KEVConfirmed exploitationCVE-2026-88771

  Citrix NetScaler ADC and NetScaler Gateway contain an improper input validation vulnerability that could allow an unauthenticated attacker to execute arbitrary commands.

  vulncheck.com

References

• CISA note · community.citrix.com
• VulnCheck exploitation evidence · dashboard.shadowserver.org
• VulnCheck exploitation evidence · labs.watchtowr.com
• CISA note · nvd.nist.gov
• CISA note · support.citrix.com
• CISA note · support.citrix.com
• US Government Resource · cisa.gov
• CISA note · cisa.gov
• CISA note · cisa.gov
• VulnCheck exploitation evidence · cisa.gov
• VulnCheck exploitation evidence · greynoise.io
• VulnCheck exploitation evidence · x.com

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.