CVE-2025-5777
Citrix NetScaler ADC and Gateway Out-of-Bounds Read Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 11 July 2025). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
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
- CVSS 4.0
- 9.3 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 99.95% probability · 100th percentile
- CISA KEV
- Listed 10 July 2025 · due 11 July 2025 · used in ransomware campaigns
- Weakness
- CWE-125, CWE-908, CWE-457
- Affected
- citrix/netscaler application delivery controller · citrix/netscaler gateway
- Source
- secure@citrix.com
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX693420 ; https://nvd.nist.gov/vuln/detail/CVE-2025-5777
References
- https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX693420Vendor Advisory
- https://citrixbleed.comBroken Link, Third Party Advisory
- https://horizon3.ai/attack-research/attack-blogs/cve-2025-5777-citrixbleed-2-write-up-maybe/Third Party Advisory
- https://labs.watchtowr.com/how-much-more-must-we-bleed-citrix-netscaler-memory-disclosure-citrixbleed-2-cve-2025-5777/Third Party Advisory
- https://www.bleepingcomputer.com/news/security/cisa-tags-citrix-bleed-2-as-exploited-gives-agencies-a-day-to-patch/Press/Media Coverage, Third Party Advisory
- https://www.netscaler.com/blog/news/netscaler-critical-security-updates-for-cve-2025-6543-and-cve-2025-5777/Third Party Advisory
- https://www.theregister.com/2025/07/10/cisa_citrixbleed_kev/Press/Media Coverage
- https://doublepulsar.com/citrixbleed-2-exploitation-started-mid-june-how-to-spot-it-f3106392aa71Third Party Advisory
- https://reliaquest.com/blog/threat-spotlight-citrix-bleed-2-vulnerability-in-netscaler-adc-gateway-devices/Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-5777US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.