Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability
Citrix · NetScaler
9.3CriticalCVSS 4.0
Recommended action
Protect now
CISA confirms exploitation in the wild and lists 2026-09-12 as the remediation due date.
Fix not verified
Optional official sources
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.
Official European source
ENISA European Vulnerability Database
Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.
1 current
ENISA EUVD identifier
EUVD-2026-62395
CISA KEV mirrored by ENISA
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.
EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 9 Sept 2026. Evidence sources: cisa_kev.
ENISA score
9.3 · CVSS 4.0
Advisory evidence
1 linked advisory record
Explicit mitigation evidence
Only statements that explicitly mention a fix, patch, update, workaround or mitigation are shown here.
csaf_ncscnl · NCSC-2026-0318Kwetsbaarheden verholpen in Citrix NetScaler ADC en NetScaler Gateway
Recommended actionProtect now
CISA confirms exploitation in the wild and lists 2026-09-12 as the remediation due date.
Fix not verified
01
What, why and how
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.
What
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.
Why
The product requires authentication, but the product has an alternate path or channel that does not require authentication.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
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.
Why
The product requires authentication, but the product has an alternate path or channel that does not require authentication.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.Confirmed in the wild
CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-09-09.
Public PoC / exploit material ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.None recorded
No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
Likely attack path
a network path → Authentication Bypass Using an Alternate Path or Channel → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness ?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-288: Authentication Bypass Using an Alternate Path or Channel. The product requires authentication, but the product has an alternate path or channel that does not require authentication.
CVSS vector ?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCLowSubsequent-system confidentiality: A successful attack can cause a limited loss.SILowSubsequent-system integrity: A successful attack can cause a limited loss.SALowSubsequent-system availability: A successful attack can cause a limited loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-288CISA KEV
A
Official authority intelligence
Only matched European and national findings are included. Language selectors and unavailable sources are omitted.
ENISA EUVD · EUVD-2026-62395Known-exploited evidence recorded
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.
Official EUVD recordBSI · German · WID-SEC-W-2026-2927Citrix Systems NetScaler (Gateway und ADC): Mehrere Schwachstellen
Ein Angreifer kann mehrere Schwachstellen in Citrix Systems NetScaler (Gateway und ADC) ausnutzen, um einen Denial of Service Angriff durchzuführen und um Sicherheitsvorkehrungen zu umgehen.
Official advisoryINCIBE-CERT · Spanish · multiples-vulnerabilidades-en-netscaler-adc-y-netscaler-0Múltiples vulnerabilidades en NetScaler ADC y NetScaler Gateway de Citrix
Citrix ha publicado 2 vulnerabilidades: 1 de severidad crítica y 1 de severidad alta que, en caso de ser explotadas, podrían permitir a un atacante omitir la autenticación mediante una ruta alternativa, provocar un comportamiento impredecible o una denegación de servicio.
Official advisoryCERT-FR · French · CERTFR-2026-AVI-1059Multiples vulnérabilités dans les produits Citrix
De multiples vulnérabilités ont été découvertes dans les produits Citrix. Elles permettent à un attaquant de provoquer un déni de service à distance, un contournement de la politique de sécurité et un problème de sécurité non spécifié par l'éditeur.
Official advisoryNBSZ-NKI · Hungarian · cve-2026-19490CVE-2026-19490
A termék megköveteli a hitelesítést, azonban az megkerülhető alternatív elérési útvonalon vagy csatornán keresztül.
Official advisoryCSIRT Italia · Italian · vulnerabilita-in-prodotti-citrix-12Vulnerabilità in prodotti Citrix
Aggiornamenti di sicurezza Citrix sanano due vulnerabilità con gravità "alta" nei prodotti NetScaler ADC (precedentemente noto come Citrix ADC) e NetScaler Gateway (precedentemente noto come Citrix Gateway).
Official advisoryNCSC-NL · Dutch · NCSC-2026-0318Kwetsbaarheden verholpen in Citrix NetScaler ADC en NetScaler Gateway
An authentication bypass vulnerability exists in NetScaler ADC and NetScaler Gateway versions 13.1 through 73.32 due to the use of an alternate path, potentially leading to security issues.
Operational remediation based on structured source evidence.
Status ?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
14.1 ≤ 73.32; 13.1 ≤ 63.21
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 19 Aug 2026 · Last source change 10 Sept 2026, 03:55 UTC · CWE-288 · Authentication Bypass Using an Alternate Path or Channel
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source ?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.FIRST · tracked since 2026-08-23
European sourceENISA EUVD · EUVD-2026-62395
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCISA ADP
NVD statusNVD enriched
Core structured fields are present and their contributing authorities are shown above.
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
CVE-2026-19490: Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability | BlackTree
