CVE-2026-88771KEV · OVERDUECWE-20

Citrix NetScaler Improper Input Validation Vulnerability

Critical · published September 27, 2026

Patch now

Confirmed exploited, and the score agrees

CVSS calls it critical at 9.8. It is confirmed in active exploitation. It sits in the 64.9th percentile for exploit probability.

24
days past CISA
deadline
CVSS v3.1
9.8
EPSS
1%
Percentile
64.9
In the wild
Confirmed
What it is

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.

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
9.5 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
EPSS
0.01083 · 64.9th percentile
Weakness
CWE-20 · Improper Input Validation
Published
2026-09-27T21:16Z
KEV added
2026-09-27 · due 2026-09-30
Affected products (7)
ProductVersionsFixed in
citrix/netscaler_application_delivery_controller≥ 13.1, < 13.1-64.2313.1-64.23
citrix/netscaler_application_delivery_controller≥ 13.1, < 13.1.37.27913.1.37.279
citrix/netscaler_application_delivery_controller≥ 13.1, < 13.1.37.27913.1.37.279
citrix/netscaler_application_delivery_controller≥ 14.1, < 14.1-73.3714.1-73.37
citrix/netscaler_application_delivery_controller≥ 14.1-66.68, ≤ 14.1-73.37—
citrix/netscaler_gateway≥ 13.1, < 13.1-64.2313.1-64.23
citrix/netscaler_gateway≥ 14.1, < 14.1-73.3714.1-73.37
References (2)
https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697096 · 50a63c94-1ea7-4568-8c11-eb79e7c5a2b5https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-88771 · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 29 SEP 03:28Z
    EPSS moved — → 1%
    epss
  • 27 SEP 16:02Z
    A remote code execution vulnerability exists due to improper input validation, which can allow an unauthenticated attacker to execute arbitrary commands
    cvelistv5
  • 27 SEP 00:00Z
    Added to CISA KEV — remediate by Sep 30
    kev