John Doe

Researcher fromAcme Security Corp
#612of 55,135
309.5Total CVSS
Vulnerabilities · 35
Medium
8
High
5
Critical
22
PT-2025-25651
10
2025-06-17
Citrix · Citrix Netscaler Gateway · CVE-2025-5777
**Name of the Vulnerable Software and Affected Versions** Citrix NetScaler Application Delivery Controller versions prior to 12.1-55.328 Citrix NetScaler Application Delivery Controller versions prior to 13.1-37.235 Citrix NetScaler Application Delivery Controller versions prior to 13.1-58.32 Citrix NetScaler Application Delivery Controller versions prior to 14.1-43.56 Citrix NetScaler Gateway versions prior to 13.1-58.32 Citrix NetScaler Gateway versions prior to 14.1-43.56 **Description** This pre-authentication memory disclosure issue occurs due to insufficient input validation, leading to a memory overread (out-of-bounds read) when the system is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server. An attacker can send a specially crafted POST request to the `/p/u/doAuthentication.do` endpoint with the `login` parameter provided without an equals sign or value. This causes the server to return fragments of uninitialized process memory within the `<InitialValue>` XML element, leaking approximately 127 bytes per request. This information can be analyzed to extract valid session tokens, enabling session hijacking and multi-factor authentication (MFA) bypass. Real-world exploitation has been observed by Anubis ransomware affiliates to gain initial access to systems, subsequently using legitimate Remote Management and Monitoring (RMM) tools to maintain persistence and deploy ransomware. **Recommendations** Update Citrix NetScaler Application Delivery Controller to version 12.1-55.328 or later. Update Citrix NetScaler Application Delivery Controller to version 13.1-37.235 or later. Update Citrix NetScaler Application Delivery Controller to version 13.1-58.32 or later. Update Citrix NetScaler Application Delivery Controller to version 14.1-43.56 or later. Update Citrix NetScaler Gateway to version 13.1-58.32 or later. Update Citrix NetScaler Gateway to version 14.1-43.56 or later. As a temporary mitigation, configure a Web Application Firewall (WAF) rule to block POST requests to the `/p/u/doAuthentication.do` endpoint that contain the `login` parameter without an assigned value.