Citrix NetScaler Improper Input Validation Vulnerability
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…
Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.
Exploitation probability EPSS · FIRST
Exploitation signals 4 / 5
- KEV catalog (CISA)27 Sept 2026
- Exploited in EUVD (ENISA)27 Sept 2026
- Used by ransomwareno
- EPSS above 10 %82.2%
- No account, over the networkyes
What to do
Fix
Apply the vendor’s fix as soon as it is available.
CISA guidance: 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.
Meanwhile
Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.
Manufacturers (CRA)
Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained
Description ENISA EUVD
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.
Affected products
- 0 <13.1-64.23
- 0 <14.1-73.37 FIPS
- 0 <14.1-73.37
- 0 <13.1.37.279 FIPS and NDcPP
Open source packages OSV
Affected libraries according to OSV, with fixed versions.
Timeline
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Published
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Exploitation reported (ENISA)
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Added to the KEV catalog
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CISA remediation due date
-
EPSS peak: 82.2%
References
Other exploited vulnerabilities from the same vendor
- CVE-2026-88779Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability6.2 · Actively exploited
- CVE-2026-88772Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability8.5 · Actively exploited
- CVE-2026-19490Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability7.1 · Actively exploited
- CVE-2026-8452Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability5.4 · Actively exploited
- CVE-2026-3055Citrix NetScaler Out-of-Bounds Read Vulnerability8.9 · Background exploitation
- CVE-2025-7775Citrix NetScaler Memory Overflow Vulnerability6.7 · Background exploitation