CVE-2026-88771
Citrix NetScaler Improper Input Validation Vulnerability
Citrix NetScaler ADC and NetScaler Gateway contain an improper input validation vulnerability that could allow an unauthenticated attacker to execute arbitrary commands.
CISA due Sep 30, 2026
- Citrix NetScaler
- Critical
- CVSS 9.5
- EPSS 4.72%
- Fixed version listed
What to do
Fixed version listed
- 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.
- CISA deadline for US federal agencies
- Sep 30, 2026
Affected products
| Product | Affected | Fixed in |
|---|---|---|
| Citrix NetScaler ADC | before 14.1-73.37; before 13.1-64.23; before 14.1-73.37 FIPS; before 13.1.37.279 FIPS and NDcPP | None listed |
| Citrix NetScaler Gateway | before 14.1-73.37; before 13.1-64.23 | 14.1-73.37 |
Scores and signals
- Exploitation
- Exploited in the wild
- Severity
- Critical, CVSS 9.5 (v4.0, scored by NetScaler)
- EPSS
- 4.72% chance of exploitation in the next 30 days (EPSS from FIRST, as of Oct 23, 2026)
- CISA's SSVC decision points
- Exploitation: active. Automatable: yes. Technical impact: total. As of Sep 27, 2026.
- Weakness
- CWE-20: Improper input validation
- Vendor
- Citrix, NetScaler
Timeline
- Added to CISA's Known Exploited Vulnerabilities catalog: exploited in the wild. US federal agencies must remediate by 2026-09-30.