CVE-2025-57071 in Tenda
Summary
by MITRE • 09/09/2025
Tenda G3 v3.0br_V15.11.0.17 was discovered to contain a stack overflow in the vpnUsers parameter in the formAddVpnUsers function. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted request.
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Analysis
by VulDB Data Team • 09/09/2025
The vulnerability identified as CVE-2025-57071 affects the Tenda G3 router firmware version 3.0br_V15.11.0.17, representing a critical stack overflow condition within the web interface administration functionality. This flaw exists in the formAddVpnUsers function where the vpnUsers parameter is processed without adequate input validation or bounds checking, creating a predictable buffer overflow scenario that can be exploited by remote attackers.
The technical implementation of this vulnerability stems from improper handling of user-supplied data within the router's web application layer. When an attacker submits a crafted request containing an excessively long vpnUsers parameter value, the application fails to validate the input length before copying it into a fixed-size stack buffer. This classic buffer overflow condition occurs because the firmware does not implement proper input sanitization or length constraints for the vpnUsers parameter, allowing the overflow to overwrite adjacent stack memory locations and potentially corrupt program execution flow.
From an operational perspective, this vulnerability presents a significant risk for network administrators and end users who rely on the Tenda G3 router for their network infrastructure. The denial of service impact means that an attacker can render the router's web management interface completely unresponsive, effectively disabling remote administration capabilities and potentially causing network disruption. The vulnerability is particularly concerning because it requires no authentication to exploit, making it accessible to anyone who can reach the router's web interface, and can be executed through simple HTTP requests targeting the affected parameter.
The security implications extend beyond simple service disruption as this vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which is categorized under the Common Weakness Enumeration framework. The attack vector follows patterns consistent with ATT&CK technique T1210 Exploitation of Remote Services, where adversaries leverage unpatched web application vulnerabilities to gain control over network devices. This particular flaw demonstrates poor input validation practices that have been consistently identified as a primary cause of memory corruption vulnerabilities in embedded network devices.
Mitigation strategies for this vulnerability should include immediate firmware updates from Tenda to address the buffer overflow condition in the formAddVpnUsers function. Network administrators should also implement network segmentation and access controls to limit exposure of the affected device to untrusted networks. Additionally, monitoring for suspicious HTTP requests containing unusually long parameter values can help detect exploitation attempts. The vulnerability highlights the importance of secure coding practices in embedded systems and the necessity of input validation and bounds checking in all user-facing application interfaces. Organizations should also consider implementing network access controls to restrict administrative access to network devices and ensure that only authorized personnel can reach management interfaces.