Citrix NetScaler ADC and Gateway Out-of-Bounds Read Vulnerability

HIGH 7.5EXPLOITED (CISA KEV)CVE-2025-5777 · Published 17/06/2025 · updated 08/10/2026

Citrix NetScaler ADC and Gateway Out-of-Bounds Read Vulnerability. Actively exploited: CISA added this vulnerability to its Known Exploited Vulnerabilities catalog on 10/07/2025. Patch affected systems as an emergency. It is known to be used in ransomware campaigns.

Package	Affected versions	Patched versions
netscaler application delivery controller citrix	`≥ 12.1, < 12.1-55.328≥ 13.1, < 13.1-37.235≥ 13.1, < 13.1-58.32≥ 14.1, < 14.1-43.56`	`12.1-55.32813.1-37.23513.1-58.3214.1-43.56`
netscaler gateway citrix	`≥ 13.1, < 13.1-58.32≥ 14.1, < 14.1-43.56`	`13.1-58.3214.1-43.56`

Description

Insufficient input validation leading to memory overread when the NetScaler is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server

References

support.citrix.com/support-home/kbsearch/article · Vendor Advisory
citrixbleed.com · Broken Link
horizon3.ai/attack-research/attack-blogs/cve-2025-5777-citrixbleed-2-write-up-maybe · Third Party Advisory
labs.watchtowr.com/how-much-more-must-we-bleed-citrix-netscaler-memory-disclosure-citrixbleed-2-cve-2025-5777 · Third Party Advisory
bleepingcomputer.com/news/security/cisa-tags-citrix-bleed-2-as-exploited-gives-agencies-a-day-to-patch · Press/Media Coverage
netscaler.com/blog/news/netscaler-critical-security-updates-for-cve-2025-6543-and-cve-2025-5777 · Third Party Advisory
theregister.com/2025/07/10/cisa_citrixbleed_kev · Press/Media Coverage
doublepulsar.com/citrixbleed-2-exploitation-started-mid-june-how-to-spot-it-f3106392aa71 · Third Party Advisory
reliaquest.com/blog/threat-spotlight-citrix-bleed-2-vulnerability-in-netscaler-adc-gateway-devices · Third Party Advisory
cisa.gov/known-exploited-vulnerabilities-catalog · US Government Resource
CISA KEV · CVE-2025-5777

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