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Findings

CVE-2026-19490

Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability

Published Aug 19, 2026 · corrected/updated Oct 7, 2026 · Citrix NetScaler · evidence confidence very high

Overview On August 19, 2026, a security advisory was published for CVE-2026-19490 , a critical authentication bypass vulnerability affecting Citrix NetScaler ADC and NetScaler Gateway. The vulnerability carries a CVSS v4.0 base score of 9.3 and can be exploited remotely by an unauthenticated attacker over the network without user interaction or elevated privileges. NetScaler ADC and NetScaler Gateway are widely deployed enterprise networking products commonly positioned at or near the network perimeter. NetScaler ADC provides application delivery, traffic management, load balancing, SSL/TLS of

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2026-19490 is a critical public vulnerability record for Citrix NetScaler. CISA lists it as known exploited. Published remediation 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. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether Citrix NetScaler is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: citrix/netscaler application delivery controller; citrix/netscaler gateway; Citrix NetScaler. Published remediation 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. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 9.3, EPSS 23.2%. CISA lists it as known exploited. Weakness classes: CWE-288. Sources contributing to this record: cisa_kev, cve_org, epss, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Confirmed in CISA KEV since Sep 9, 2026. Listed in the CISA Known Exploited Vulnerabilities catalog.

  • Patch and remediation

    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. CISA due date Sep 12, 2026.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 19, 2026 · Catalog

    Detected

    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.

  2. Sep 9, 2026 · CISA KEV

    Known exploited

    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

  3. Sep 12, 2026 · CISA KEV

    Remediation due

    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

  4. Oct 7, 2026 · Catalog

    Updated

    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.

Affected

  • cpe citrix/netscaler application delivery controllerversion unspecified
  • cpe citrix/netscaler gatewayversion unspecified
  • vendor Citrix NetScalerversion unspecified

Sources

  • CISA KEVConfirmed exploitationCVE-2026-19490

    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.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2026-19490

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-19490

    30-day exploitation probability 23.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-19490

    Vulnerability in NetScaler ADC and NetScaler Gateway. This issue affects ADC: from 14.1 through 73.32 and from 13.1 through 63.21; Gateway: from 14.1 through 73.32 and from 13.1 through 63.21.

    nvd.nist.gov
  • Rapid7 Vulnerability DatabaseResearchCVE-2026-19490

    Overview On August 19, 2026, a security advisory was published for CVE-2026-19490 , a critical authentication bypass vulnerability affecting Citrix NetScaler ADC and NetScaler Gateway. The vulnerability carries a CVSS v4.0 base score of 9.3 and can be exploited remotely by an unauthenticated attacker over the network without user interaction or elevated privileges. NetScaler ADC and NetScaler Gate

    rapid7.com

References