CVE-2025-12619: Tenda A15 Buffer Overflow Vulnerability

CVE-2025-12619 Overview

A buffer overflow vulnerability has been discovered in Tenda A15 wireless router firmware version 15.13.07.13. The vulnerability exists in the fromSetWirelessRepeat function within the /goform/openNetworkGateway endpoint. Improper handling of the wpapsk_crypto2_4g argument allows an attacker to trigger a buffer overflow condition, potentially leading to arbitrary code execution or denial of service. The vulnerability can be exploited remotely over the network, making it a significant security concern for users of affected devices. The exploit has been disclosed publicly, increasing the risk of exploitation.

Critical Impact

Remote attackers can exploit this buffer overflow vulnerability to potentially execute arbitrary code or crash affected Tenda A15 routers, compromising network security and availability.

Affected Products

• Tenda A15 Firmware version 15.13.07.13
• Tenda A15 Hardware Device

Discovery Timeline

• November 3, 2025 - CVE-2025-12619 published to NVD
• November 5, 2025 - Last updated in NVD database

Technical Details for CVE-2025-12619

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 fromSetWirelessRepeat function in the Tenda A15 firmware fails to properly validate the length of user-supplied input passed through the wpapsk_crypto2_4g parameter. When an attacker submits a maliciously crafted request to the /goform/openNetworkGateway endpoint with an oversized value for this parameter, the function copies the data into a fixed-size buffer without proper bounds checking, resulting in a classic stack-based buffer overflow condition.

The vulnerability allows authenticated remote attackers to corrupt adjacent memory regions, potentially overwriting return addresses or other critical data structures. This can lead to arbitrary code execution in the context of the router's firmware, allowing complete device compromise, or result in a denial of service condition by crashing the affected process.

Root Cause

The root cause of this vulnerability is insufficient input validation in the fromSetWirelessRepeat function. The firmware fails to verify that the length of the wpapsk_crypto2_4g argument does not exceed the allocated buffer size before performing the copy operation. This is a common vulnerability pattern in embedded device firmware where developers may not implement proper bounds checking on user-controllable input fields.

Attack Vector

The attack can be conducted remotely over the network. An attacker with low-privilege access to the router's web management interface can craft a malicious HTTP POST request to the /goform/openNetworkGateway endpoint. By supplying an excessively long string in the wpapsk_crypto2_4g parameter, the attacker can overflow the internal buffer and potentially gain control of program execution flow.

The vulnerability is accessible via the router's web interface, which is typically exposed on the local network. If the management interface is inadvertently exposed to the internet or if an attacker has already gained access to the local network, the risk of exploitation increases significantly.

The vulnerability manifests when the fromSetWirelessRepeat function processes wireless repeater configuration parameters without adequate length validation. Technical analysis and additional details are available through the VulDB Exploit Entry and the Yuque Document Analysis.

Detection Methods for CVE-2025-12619

Indicators of Compromise

• Unexpected router reboots or service disruptions without apparent cause
• Unusual HTTP POST requests to /goform/openNetworkGateway with abnormally long parameter values
• Modified router configuration or unauthorized wireless repeater settings
• Network traffic anomalies originating from the router device

Detection Strategies

• Monitor web server logs for requests to /goform/openNetworkGateway containing oversized wpapsk_crypto2_4g parameter values
• Implement network intrusion detection rules to identify HTTP requests with excessively long form parameters targeting Tenda devices
• Deploy web application firewall rules to block requests exceeding expected parameter lengths
• Establish baseline behavior monitoring for router management interface access patterns

Monitoring Recommendations

• Enable logging on network firewalls to capture traffic destined for router management interfaces
• Configure alerts for repeated failed authentication attempts followed by successful access to configuration endpoints
• Monitor for firmware integrity changes or unexpected modifications to router settings
• Review network segmentation to ensure router management interfaces are not exposed to untrusted networks

How to Mitigate CVE-2025-12619

Immediate Actions Required

• Restrict access to the router's web management interface to trusted IP addresses only
• Disable remote management features if not required for operations
• Implement network segmentation to isolate IoT and network devices from general user traffic
• Monitor for suspicious activity targeting router administration endpoints
• Consider replacing affected devices if no vendor patch is available

Patch Information

At the time of publication, no official patch information from Tenda has been identified in the available references. Users should monitor the Tenda Official Website for security updates and firmware releases addressing this vulnerability. Given the public disclosure of this exploit, applying any available patches should be treated as a priority.

Workarounds

• Disable the wireless repeater functionality if not actively used to reduce the attack surface
• Implement strong authentication and change default credentials on the router's management interface
• Use firewall rules to restrict management interface access to specific trusted hosts
• Consider placing the router behind a separate firewall that can filter malicious requests
• Evaluate alternative router solutions if Tenda does not release a timely security update

# Example firewall rule to restrict management access (iptables)
# Replace 192.168.1.100 with your trusted management IP
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.100 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP