CVE-2025-12622: Tenda AC10 Buffer Overflow Vulnerability

CVE-2025-12622 Overview

A buffer overflow vulnerability has been identified in the Tenda AC10 router firmware version 16.03.10.13. This vulnerability exists within the formSysRunCmd function located in the /goform/SysRunCmd endpoint. Improper handling of the getui argument allows an attacker to trigger a buffer overflow condition, potentially leading to remote code execution or denial of service on affected devices.

Critical Impact

Remote attackers with low-level privileges can exploit this buffer overflow vulnerability over the network to compromise Tenda AC10 routers, potentially gaining full control of the device or causing service disruption.

Affected Products

• Tenda AC10 Firmware version 16.03.10.13
• Tenda AC10 Hardware version 4.0
• Tenda AC10 Router devices running vulnerable firmware

Discovery Timeline

• 2025-11-03 - CVE-2025-12622 published to NVD
• 2025-11-05 - Last updated in NVD database

Technical Details for CVE-2025-12622

Vulnerability Analysis

This vulnerability is a classic buffer overflow condition (CWE-119, CWE-120) affecting the Tenda AC10 router's web management interface. The vulnerable function formSysRunCmd processes user-supplied input from the getui parameter without proper bounds checking. When specially crafted input exceeding the expected buffer size is submitted to the /goform/SysRunCmd endpoint, it overwrites adjacent memory regions.

The exploit has been publicly disclosed, increasing the risk of active exploitation against unpatched devices. Network-attached routers are particularly attractive targets as they often serve as the security perimeter for home and small business networks.

Root Cause

The root cause of this vulnerability lies in improper input validation within the formSysRunCmd function. The code fails to verify that the length of data received via the getui argument does not exceed the allocated buffer size before copying it into memory. This classic buffer overflow pattern allows attackers to overwrite stack or heap memory, potentially corrupting control flow data structures.

Attack Vector

The vulnerability is exploitable remotely over the network. An attacker with low-level authentication to the router's web interface can send a maliciously crafted HTTP request to the /goform/SysRunCmd endpoint containing an oversized getui parameter value. The attack does not require user interaction beyond the initial authentication.

The exploitation mechanism involves submitting an HTTP POST request to the vulnerable endpoint with the getui parameter containing data that exceeds the expected buffer length. When processed by the formSysRunCmd function, this oversized input overwrites adjacent memory, potentially allowing arbitrary code execution or causing a denial of service condition. Technical details and proof-of-concept information have been documented in the Yuque Document Analysis and VulDB #330914.

Detection Methods for CVE-2025-12622

Indicators of Compromise

• Unusual HTTP POST requests to /goform/SysRunCmd with oversized getui parameter values
• Router crashes or unexpected reboots indicating potential exploitation attempts
• Abnormal outbound network connections from the router to unknown external hosts
• Modified router configuration or firmware settings without administrator action

Detection Strategies

• Monitor network traffic for HTTP requests targeting /goform/SysRunCmd with unusually large payload sizes
• Implement intrusion detection rules to flag buffer overflow patterns in web requests to Tenda router management interfaces
• Review router logs for repeated access attempts to the vulnerable endpoint
• Deploy network-based anomaly detection to identify exploitation attempts

Monitoring Recommendations

• Enable detailed logging on network firewalls and intrusion detection systems for traffic destined to Tenda router management ports
• Configure alerts for any access to the /goform/SysRunCmd endpoint from untrusted network segments
• Regularly audit router firmware versions across the network to identify vulnerable devices
• Monitor for any signs of router compromise including DNS setting changes or unauthorized port forwarding rules

How to Mitigate CVE-2025-12622

Immediate Actions Required

• Restrict access to the router's web management interface to trusted networks only
• Disable remote management features if not required for operations
• Place vulnerable Tenda AC10 routers behind additional network security controls
• Monitor the Tenda Official Website for firmware security updates

Patch Information

As of the last NVD update on 2025-11-05, no official patch has been released by Tenda for this vulnerability. Organizations should monitor vendor communications and apply firmware updates as soon as they become available. Additional technical references are available through VulDB CTI ID #330914.

Workarounds

• Configure firewall rules to block external access to the router's management interface on ports 80 and 443
• Implement network segmentation to isolate vulnerable routers from critical network assets
• Use a VPN for remote management instead of exposing the web interface directly
• Consider replacing vulnerable devices with alternative hardware if patches are not forthcoming

# Example: Block external access to router management interface
# Add to upstream firewall or network ACL

# Block HTTP access to management interface from WAN
iptables -A FORWARD -p tcp --dport 80 -d <ROUTER_IP> -j DROP
iptables -A FORWARD -p tcp --dport 443 -d <ROUTER_IP> -j DROP

# Allow management access only from trusted admin subnet
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT