CVE-2026-8451 in NetScaler ADC
Summary
by MITRE • 06/30/2026
Insufficient input validation in NetScaler ADC and NetScaler Gateway leading to memory overread if NetScaler ADC or NetScaler Gateway is configured as a SAML IDP
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Analysis
by VulDB Data Team • 07/04/2026
This vulnerability represents a critical security flaw in Citrix NetScaler ADC and NetScaler Gateway appliances when configured as Security Assertion Markup Language identity providers. The issue stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data during SAML authentication processes. When a malicious actor crafts specially formatted SAML requests or responses, the system attempts to process these inputs without sufficient validation checks, leading to memory overread conditions where the application accesses memory locations beyond the intended buffer boundaries.
The technical exploitation occurs when the NetScaler appliance receives malformed SAML assertions or authentication requests that contain oversized or malformed parameters. This insufficient validation allows attackers to manipulate the parsing logic and cause the system to read beyond allocated memory segments, potentially exposing sensitive data from adjacent memory regions. The vulnerability specifically affects scenarios where the appliance functions as a SAML identity provider, making it particularly dangerous in enterprise environments that rely on Citrix appliances for single sign-on authentication services.
From an operational perspective, this vulnerability creates significant risk exposure for organizations utilizing Citrix NetScaler solutions in their authentication infrastructure. Attackers could potentially extract confidential information including session tokens, user credentials, or system configuration details from memory dumps. The impact extends beyond simple data leakage as the memory overread conditions may also lead to application instability, denial of service scenarios, or even facilitate further exploitation attempts. Organizations with extensive SAML-based authentication deployments face heightened risk since the vulnerability can be exploited remotely without requiring prior authentication.
Security frameworks such as CWE-129 and CWE-787 provide relevant context for understanding this vulnerability pattern, where inadequate input validation leads to buffer overread conditions that can result in information disclosure or system compromise. The ATT&CK framework categorizes this under T1566 for credential access through exploitation of authentication systems and potentially T1005 for data from local system memory extraction. Mitigation strategies should include immediate application of Citrix security patches, implementation of network-level restrictions on SAML traffic, deployment of intrusion detection systems to monitor for suspicious SAML request patterns, and comprehensive input validation enforcement within the appliance configuration. Organizations should also consider isolating affected appliances in segmented network environments and implementing additional monitoring controls to detect anomalous authentication behavior that might indicate exploitation attempts.