CISA Warns of Citrix NetScaler Authentication Bypass Vulnerability Exploited in Attacks

Cybersecuritynews •Abinaya • September 10, 2026

CISA added a critical Citrix NetScaler authentication bypass flaw (CVE-2026-19490) to its Known Exploited Vulnerabilities catalog after observing in-the-wild attacks targeting the issue. Federal civilian agencies must apply vendor mitigations by September 12, 2026. CVE-2026-19490 affects Citrix NetScaler ADC and NetScaler Gateway appliances configured as an Authentication, Authorization and Auditing virtual server or as a […]

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Exploitation of Citrix NetScaler Authentication Bypass Vulnerability CVE-2026-19490 On September 4, 2026, it was reported that threat actors are actively targeting a critical authentication bypass vulnerability in Citrix NetScaler, tracked as CVE-2026-19490. This flaw allows unauthenticated attackers to bypass authentication controls on affected NetScaler ADC and Gateway deployments, potentially granting access to sensitive applications. The vulnerability was publicly disclosed on August 19, 2026, and a proof-of-concept exploit was released on September 3, 2026. Citrix has urged organizations to apply security updates and monitor for unauthorized access. The CVE has a CVSS v4.0 score of 9.3, indicating its critical severity. Organizations using NetScaler products are advised to assess their configurations and apply patches immediately. The Australian Cyber Security Centre has issued warnings, although no specific sectors are currently reported as targeted. 15 sources 73

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CISA Warns of Citrix NetScaler Authentication Bypass Vulnerability Exploited in Attacks

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