CVE-2025-5777
Citrix NetScaler ADC and Gateway Out-of-Bounds Read Vulnerability
Citrix NetScaler ADC and Gateway
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
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 10 July 2025. US federal agencies were required to remediate it by 11 July 2025. CISA records this vulnerability as known to be used in ransomware campaigns.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 100%, which is higher than 99.9% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Frequently asked questions
Is CVE-2025-5777 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2025-5777.
What does CVE-2025-5777 affect?
CVE-2025-5777 affects Citrix NetScaler ADC and Gateway. 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
How severe is CVE-2025-5777?
CVE-2025-5777 is rated HIGH with a CVSS base score of 7.5. EPSS puts the probability of exploitation in the next 30 days at 100%, higher than 99.9% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 11 July 2025.
How should organisations respond to CVE-2025-5777?
Apply the vendor patch for Citrix NetScaler ADC and Gateway as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.