CISA Adds Actively Exploited Citrix NetScaler Vulnerability to KEV Catalog

CVE-2026-3055, an out-of-bounds read vulnerability in Citrix NetScaler, has been added to CISA's Known Exploited Vulnerabilities Catalog due to evidence of active exploitation in the wild. This vulnerability affects critical network infrastructure components that are often internet-facing, making them attractive targets for attackers. The inclusion in the KEV catalog under BOD 22-01 indicates this vulnerability poses significant risk and requires immediate attention from all organizations, not just federal agencies. Organizations that fail to patch this vulnerability quickly may face data breaches, network compromise, or service disruptions.

Tactical Insight

Immediate actions

Patch all Citrix NetScaler appliances to the latest version immediately
Scan network infrastructure for vulnerable NetScaler instances
Monitor logs for signs of exploitation attempts on NetScaler systems

Long-term improvements

Implement automated vulnerability scanning for all internet-facing network appliances
Establish emergency patching procedures for critical infrastructure components
Maintain comprehensive asset inventory including all network security devices

Detection measures

Deploy network monitoring to detect unusual traffic patterns from NetScaler appliances
Configure SIEM alerts for exploitation indicators related to this CVE