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Citrix NetScaler Gateway Authentication Bypass Exposes Thousan...

A critical authentication bypass in Citrix NetScaler Gateway and ADC allows attackers to access protected resources without valid credentials.

By Danny Mercer, CISSP — Lead Security Analyst Feb 28, 2026

Executive Summary

CVE-2026-4966 allows unauthenticated access to protected resources through session validation flaws. Over 45,000 NetScaler instances exposed to internet. PoC code circulating.

Technical Analysis

Certain authentication configurations allow attackers to craft requests processed as already-authenticated sessions. Affects versions 13.0, 13.1, and 14.1 before patched releases.

Remediation

Patch immediately. Responder policies available as temporary mitigation. Enable detailed logging and monitor for unusual access patterns.

References

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