CVE-2025-9523: Tenda AC1206 Buffer Overflow Vulnerability

CVE-2025-9523 Overview

A stack-based buffer overflow vulnerability has been identified in the Tenda AC1206 router running firmware version 15.03.06.23. The vulnerability exists in the GetParentControlInfo function located in the /goform/GetParentControlInfo endpoint. Remote attackers can exploit this vulnerability by manipulating the mac argument, causing a stack-based buffer overflow that could lead to arbitrary code execution or denial of service on the affected device.

Critical Impact

This network-accessible vulnerability allows unauthenticated remote attackers to potentially execute arbitrary code or crash the device by sending specially crafted requests to the router's web interface. The exploit has been publicly disclosed, increasing the risk of widespread exploitation.

Affected Products

• Tenda AC1206 Firmware version 15.03.06.23
• Tenda AC1206 Hardware

Discovery Timeline

• August 27, 2025 - CVE-2025-9523 published to NVD
• September 20, 2025 - Last updated in NVD database

Technical Details for CVE-2025-9523

Vulnerability Analysis

This vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw resides in the GetParentControlInfo function, which processes user-supplied input through the mac parameter without adequate bounds checking. When an attacker provides an oversized or malformed mac value, the function writes data beyond the allocated buffer space on the stack, corrupting adjacent memory regions.

The vulnerability is exploitable remotely over the network without any authentication requirements. An attacker can send a crafted HTTP request to the /goform/GetParentControlInfo endpoint with a malicious mac parameter value. Due to the nature of stack-based buffer overflows in embedded systems running minimal operating systems, successful exploitation could allow attackers to overwrite the return address and redirect execution flow to attacker-controlled code.

Root Cause

The root cause is insufficient input validation and boundary checking in the GetParentControlInfo function when handling the mac argument. The function fails to verify that the input length does not exceed the allocated buffer size before copying the data to the stack. This classic memory corruption pattern is common in embedded device firmware where security practices may be less rigorous than in mainstream software development.

Attack Vector

The attack can be executed remotely over the network. An attacker with network access to the router's web management interface can craft malicious HTTP requests targeting the vulnerable endpoint. The attack requires no authentication and no user interaction, making it particularly dangerous for devices exposed to the internet or accessible from an untrusted network segment.

The vulnerable endpoint /goform/GetParentControlInfo accepts the mac parameter, which when provided with an excessively long or specially crafted value, triggers the buffer overflow condition. Detailed technical information about this vulnerability is available in the GitHub IoT CVE Documentation.

Detection Methods for CVE-2025-9523

Indicators of Compromise

• Unusual or oversized HTTP requests to /goform/GetParentControlInfo endpoint
• Unexpected router reboots or crashes indicating exploitation attempts
• Anomalous network traffic patterns originating from or destined to the router's management interface
• Log entries showing requests with abnormally long mac parameter values

Detection Strategies

• Monitor HTTP traffic to router management interfaces for requests containing unusually long parameter values in the mac field
• Deploy network intrusion detection rules to identify buffer overflow attack patterns targeting Tenda router endpoints
• Implement deep packet inspection for traffic to /goform/GetParentControlInfo to detect exploitation attempts
• Use SentinelOne Singularity platform to monitor for anomalous behavior patterns on network segments containing vulnerable devices

Monitoring Recommendations

• Enable logging on all network access to router management interfaces
• Configure alerts for multiple failed or malformed requests to goform endpoints
• Monitor for unexpected device reboots which may indicate successful exploitation followed by system crash
• Implement network segmentation monitoring to detect lateral movement from compromised IoT devices

How to Mitigate CVE-2025-9523

Immediate Actions Required

• Restrict network access to the router's web management interface to trusted IP addresses only
• Disable remote management access if not strictly required
• Segment the network to isolate IoT and network infrastructure devices from untrusted networks
• Monitor the Tenda Official Website for firmware updates addressing this vulnerability

Patch Information

At the time of publication, no official patch has been released by Tenda for this vulnerability. Organizations should monitor vendor channels for security updates. The vulnerability affects Tenda AC1206 firmware version 15.03.06.23. Additional technical details can be found at VulDB ID #321541.

Workarounds

• Disable the web management interface entirely if not required for operations
• Implement firewall rules to block external access to the router's management ports
• Use a VPN or out-of-band management network for administrative access to the device
• Consider replacing vulnerable devices with alternative products that receive regular security updates

# Example firewall rule to restrict access to router management interface
# Block external access to common router management ports
iptables -A INPUT -p tcp --dport 80 -s ! 192.168.1.0/24 -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 192.168.1.0/24 -j DROP

# Allow management access only from specific trusted IP
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.100 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.100 -j ACCEPT