CVE-2025-4298: Tenda AC1206 Buffer Overflow Vulnerability

CVE-2025-4298 Overview

A critical buffer overflow vulnerability has been identified in Tenda AC1206 wireless routers running firmware versions up to 15.03.06.23. The vulnerability exists in the formSetCfm function located in the /goform/setcfm endpoint, where improper handling of user-supplied input leads to a buffer overflow condition. This flaw allows remote authenticated attackers to potentially execute arbitrary code or cause denial of service on affected devices.

Critical Impact

Remote attackers with low privileges can exploit this buffer overflow vulnerability to compromise the integrity, confidentiality, and availability of Tenda AC1206 routers, potentially gaining full control over the network device.

Affected Products

• Tenda AC1206 Firmware versions up to 15.03.06.23
• Tenda AC1206 Hardware devices

Discovery Timeline

• 2025-05-06 - CVE-2025-4298 published to NVD
• 2025-05-13 - Last updated in NVD database

Technical Details for CVE-2025-4298

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-120 (Buffer Copy without Checking Size of Input). The formSetCfm function in the Tenda AC1206 firmware fails to properly validate the length of user-supplied input before copying it into a fixed-size buffer. When processing requests to the /goform/setcfm endpoint, the function does not implement adequate bounds checking, allowing attackers to overflow the buffer with crafted malicious input.

The exploit has been publicly disclosed, making this vulnerability particularly concerning for organizations with exposed Tenda AC1206 devices. Technical details and proof-of-concept documentation have been made available through GitHub PoC Documentation.

Root Cause

The root cause of this vulnerability stems from the lack of proper input validation and bounds checking in the formSetCfm function. The firmware code directly copies user-controlled data into a fixed-size stack or heap buffer without verifying that the input length does not exceed the allocated buffer size. This classic buffer overflow condition (CWE-120) results from unsafe memory operations that fail to sanitize or truncate input data before processing.

Attack Vector

The vulnerability is exploitable remotely over the network with low attack complexity. An attacker with low-level privileges on the device can send specially crafted HTTP requests to the /goform/setcfm endpoint. The malicious payload, when processed by the formSetCfm function, triggers a buffer overflow that can corrupt adjacent memory regions. Depending on the memory layout and the attacker's payload, this can lead to arbitrary code execution, device crashes, or complete system compromise.

The vulnerability can be exploited by sending malformed HTTP POST requests to the affected endpoint with oversized input parameters designed to overflow the vulnerable buffer. For detailed exploitation methodology, see the GitHub PoC Documentation.

Detection Methods for CVE-2025-4298

Indicators of Compromise

• Unusual HTTP POST requests to /goform/setcfm containing abnormally long parameter values
• Unexpected router reboots or crashes that may indicate exploitation attempts
• Anomalous network traffic patterns originating from or directed at Tenda AC1206 devices
• Evidence of unauthorized configuration changes on the router

Detection Strategies

• Monitor HTTP traffic to Tenda AC1206 management interfaces for requests exceeding normal parameter lengths
• Implement intrusion detection system (IDS) rules to detect buffer overflow payloads targeting /goform/setcfm
• Deploy network-based anomaly detection to identify suspicious traffic patterns to router endpoints
• Enable logging on network perimeter devices to capture requests to vulnerable firmware endpoints

Monitoring Recommendations

• Configure network monitoring tools to alert on HTTP requests to /goform/ endpoints with large payload sizes
• Review router access logs regularly for signs of exploitation attempts or unauthorized access
• Implement network segmentation to isolate IoT devices and limit exposure of management interfaces
• Monitor for unexpected outbound connections from router devices that could indicate compromise

How to Mitigate CVE-2025-4298

Immediate Actions Required

• Restrict access to the router's web management interface to trusted networks only
• Disable remote administration features if not required
• Implement firewall rules to block external access to the router's management ports
• Consider replacing affected devices with supported alternatives if no patch is available

Patch Information

As of the last modification date (2025-05-13), no official patch information has been published by Tenda for this vulnerability. Users should monitor the Tenda Official Website for firmware updates and security advisories. Additional vulnerability details are available through VulDB Entry #307402.

Workarounds

• Configure access control lists (ACLs) to restrict management interface access to specific trusted IP addresses
• Place the router behind an additional firewall layer to filter malicious requests
• Disable the web-based management interface and use alternative configuration methods if available
• Consider network segmentation to limit the blast radius of a potential compromise

# Example: Restrict management access via upstream firewall
# Block external access to router management port (example for iptables)
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP

# Block access to vulnerable endpoint from untrusted networks
iptables -A FORWARD -d <router_ip> -p tcp --dport 80 -m string --string "/goform/setcfm" --algo bm -j DROP