Exploited vulnerability · CISA KEV
Yes. CVE-2026-19490, Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 9 Sep 2026, 21 days after it was published. It affects Citrix NetScaler, an internet-facing product of the kind attackers use for initial access. If you run it, CISA's required action is: 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.
Citrix NetScaler ADC and NetScaler Gateway contain an authentication-bypass vulnerability involving an alternate path or channel. When the NetScaler appliance is configured as an AAA virtual server or as a Gateway (SSL VPN, ICA Proxy, CVPN, or RDP Proxy), an unauthenticated remote threat actor may be able to bypass authentication.
| Vendor | Citrix (27 exploited CVEs in KEV) |
| Product | NetScaler |
| Vulnerability | Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability |
| Weakness | CWE-288 |
| Published | 19 Aug 2026 |
| Added to KEV | 9 Sep 2026 |
| Reported by (CNA) | NetScaler |
Yes. CISA added CVE-2026-19490 to the Known Exploited Vulnerabilities catalog on 9 Sep 2026, which means there is reliable evidence of exploitation in the wild.
CISA does not list known ransomware use for it. That can change, and exploitation alone is reason to fix it first.
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. Check Citrix's advisory for the fixed versions, and if you can't patch quickly, restrict access to the affected NetScaler and watch it for signs of compromise.
Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in September 2026 · Citrix scorecard · act-now radar.
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