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CISA KEV Alert โ Active Real-World Exploitation Confirmed
This vulnerability is in the CISA Known Exploited Vulnerabilities catalog and is being actively exploited right now.
Citrix NetScaler Critical RCE Exploited (CVE-2026-3055) | MSSP Advisory
Critical๐ด KEV ALERTConfirmed
DateApril 21, 2026
CVECVE-2026-3055
CVSS Score9.8
Affectednetscaler_application_delivery_controller, netscaler_gateway
Risk Assessment
Client Exposure:High
Briefing Priority:Immediate
Barrier to Entry:Low
๐Executive Summary
CVE-2026-3055 is a critical vulnerability in Citrix NetScaler appliances that attackers are actively exploiting in the wild according to watchTowr and Defused researchers. The vulnerability allows remote code execution on NetScaler systems that serve as the gateway between remote users and internal networks. Attack campaigns are targeting unpatched NetScaler instances to gain initial access to corporate environments.
โ ๏ธWhy It Matters for MSSPs
NetScaler appliances sit at the network perimeter for most mid-market clients, making them a direct path to compromise client environments if exploited. Your own remote access infrastructure likely depends on NetScaler or similar SSL VPN appliances that become the breach point if left unpatched. Active exploitation means attackers are scanning for vulnerable instances right now.
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Recommended Action
Immediately inventory all client NetScaler deployments and push emergency patching within 24 hours for any instances running vulnerable firmware versions.
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๐ท๏ธThreat Category
Zero-Day
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