CVE-2016-10176 in WNR2000v5
Summary
by MITRE
The NETGEAR WNR2000v5 router allows an administrator to perform sensitive actions by invoking the apply.cgi URL on the web server of the device. This special URL is handled by the embedded web server (uhttpd) and processed accordingly. The web server also contains another URL, apply_noauth.cgi, that allows an unauthenticated user to perform sensitive actions on the device. This functionality can be exploited to change the router settings (such as the answers to the password-recovery questions) and achieve remote code execution.
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Analysis
by VulDB Data Team • 05/16/2026
The CVE-2016-10176 vulnerability affects the NETGEAR WNR2000v5 router model and represents a critical authentication bypass flaw within the device's web-based management interface. This vulnerability stems from improper access control mechanisms within the embedded web server implementation, specifically the uhttpd web server component that handles administrative functions. The flaw manifests through two distinct URL endpoints that provide unauthorized access to sensitive administrative operations, creating a significant security risk for network administrators and end users who rely on these devices for network connectivity and security.
The technical implementation of this vulnerability involves the presence of two web endpoints within the router's embedded web server that should normally require authentication but instead allow unauthorized access to administrative functions. The primary endpoint apply.cgi typically requires valid administrative credentials to execute sensitive operations, while the secondary apply_noauth.cgi endpoint operates without any authentication requirements. This design flaw allows an attacker to directly access the apply_noauth.cgi URL and perform administrative actions that should be restricted to authorized users only. The vulnerability specifically targets the router's configuration management system, enabling modification of critical settings including password recovery questions and other administrative parameters.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it provides attackers with the capability to completely compromise router functionality and potentially escalate privileges to achieve remote code execution. When an attacker successfully exploits this vulnerability, they can modify router configuration parameters, change administrative credentials, alter network settings, and manipulate security features such as password recovery mechanisms. The ability to change password recovery questions particularly undermines the device's security model, as it allows attackers to gain persistent access to the router's administrative interface. This vulnerability essentially provides a backdoor into the router's management system that can be exploited from any network location without requiring prior authentication or knowledge of existing credentials.
The exploitation of this vulnerability aligns with multiple attack patterns documented in the ATT&CK framework, specifically targeting the privilege escalation and persistence phases of an attack lifecycle. The vulnerability directly maps to CWE-285: Improper Authorization, which describes situations where an application does not properly verify that the user has sufficient permissions to perform a requested operation. This flaw also demonstrates characteristics of CWE-352: Cross-Site Request Forgery, as it allows unauthorized actions to be performed through web requests without proper authentication verification. Network administrators should note that this vulnerability affects devices running firmware versions that include the problematic uhttpd web server implementation, making it particularly concerning for organizations with legacy network infrastructure that may not receive regular firmware updates.
Mitigation strategies for this vulnerability require immediate action from affected organizations, including firmware updates from NETGEAR that address the authentication bypass flaw and proper network segmentation to limit access to administrative interfaces. The most effective immediate solution involves disabling remote administration capabilities and restricting access to the router's web interface to trusted network segments only. Network administrators should also implement monitoring for suspicious access patterns to the apply_noauth.cgi endpoint and ensure that all administrative interfaces are protected by strong authentication mechanisms. Regular security audits of network infrastructure should include verification of device firmware versions and confirmation that administrative interfaces are properly secured against unauthorized access attempts. Organizations should also consider implementing network access control lists that restrict access to router management interfaces to specific administrative workstations and establish proper change management procedures for router configuration modifications.