CVE-2026-19490: Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 21 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 32.7%
EPSS score, percentile 98.3 of all scored records
- How severe?
- 9.3 Critical
CVSS v4.0 base score, given by the CNA
- What should I do?
CISA deadline . Apply mitigations in accordance with vendor instructions … Full text
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- 14.1 through 73.32
- 13.1 through 63.21
- 14.1 through 73.32
- 13.1 through 63.21
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
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 for this action: .
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
- https://support.citrix.com/external/article/CTX696939/netscaler-adc-and-netscaler-gateway-secu.html
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2026-19490
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | 14.1 through 73.32 |
| Affected | 13.1 through 63.21 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | 14.1 through 73.32 |
| Affected | 13.1 through 63.21 |
Versions not listed are: unaffected.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
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.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2026-19490 to its Known Exploited Vulnerabilities (KEV) catalog on 9 Sep 2026.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 12 Sep 2026.
- The CVE record was published on 19 Aug 2026, 21 days before it was added to KEV.
- The CVE record carries a CVSS v4.0 base score of 9.3 (Critical), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 32.7% (percentile 98.3), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
Description
NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-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.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
- CWE-288: Authentication Bypass Using an Alternate Path or Channel
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CISA due date for the required action | |
| CVE record last updated |
References
More exploited Citrix vulnerabilities
- CVE-2026-88779: Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
- CVE-2026-88771: Citrix NetScaler Improper Input Validation Vulnerability
- CVE-2026-88772: Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
- CVE-2026-8452: Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
- CVE-2026-3055: Citrix NetScaler Out-of-Bounds Read Vulnerability
- CVE-2025-7775: Citrix NetScaler Memory Overflow Vulnerability