CVE-2026-88771
Published 2026-09-27 · Updated 2026-09-29 · Source 50a63c94-1ea7-4568-8c11-eb79e7c5a2b5
Summary
CVE-2026-88771 is a critical-severity (CVSS 9.8) vulnerability in Citrix NetScaler. CISA added it to the Known Exploited Vulnerabilities catalog on September 27, 2026, which means exploitation in the wild has been confirmed; US federal agencies had to remediate it by September 30, 2026. CISA does not currently list it as used in ransomware campaigns. Citrix has 27 vulnerabilities in the KEV catalog, 7 of them linked to ransomware.
All 27 known-exploited Citrix vulnerabilities →Description
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.
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA Known-Exploited Vulnerability
Product: Citrix — NetScaler
Name: Citrix NetScaler Improper Input Validation Vulnerability
Date added: 2026-09-27 · Due: 2026-09-30
Required action: 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.