CVE-2025-12232: Tenda CH22 Buffer Overflow Vulnerability

CVE-2025-12232 Overview

A buffer overflow vulnerability has been identified in Tenda CH22 firmware version 1.0.0.1. The vulnerability exists in the fromSafeClientFilter function within the file /goform/SafeClientFilter. By manipulating the page argument, an attacker can trigger a buffer overflow condition. This vulnerability can be exploited remotely, and the exploit is publicly available, increasing the risk of active exploitation.

Critical Impact

Remote attackers can exploit this buffer overflow to potentially achieve arbitrary code execution or cause denial of service on affected Tenda CH22 devices.

Affected Products

• Tenda CH22 Firmware version 1.0.0.1
• Tenda CH22 Hardware (all versions)

Discovery Timeline

• October 27, 2025 - CVE-2025-12232 published to NVD
• February 24, 2026 - Last updated in NVD database

Technical Details for CVE-2025-12232

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw resides in the web interface component of the Tenda CH22 router, specifically within the fromSafeClientFilter function that handles client filtering operations. When processing the page parameter, the function fails to properly validate the input length before copying it into a fixed-size buffer, creating a classic buffer overflow condition.

The vulnerability can be triggered remotely over the network with low attack complexity. An attacker with low privileges on the target system can craft malicious requests to the /goform/SafeClientFilter endpoint, potentially compromising the confidentiality, integrity, and availability of the device.

Root Cause

The root cause of this vulnerability is improper bounds checking in the fromSafeClientFilter function. The function accepts user-supplied input via the page argument without validating its length against the destination buffer's capacity. This allows an attacker to provide input that exceeds the buffer size, causing memory corruption.

Attack Vector

The attack is network-based and can be executed remotely. An attacker can send specially crafted HTTP requests to the /goform/SafeClientFilter endpoint on vulnerable Tenda CH22 devices. By providing an oversized value for the page parameter, the attacker can overflow the buffer and potentially:

1. Overwrite adjacent memory regions
2. Corrupt function return addresses on the stack
3. Execute arbitrary code in the context of the web server process
4. Cause the device to crash, resulting in denial of service

The vulnerability requires low privileges to exploit, suggesting that basic authentication to the device's web interface may be necessary. No user interaction is required for exploitation.

For detailed technical information about this vulnerability, refer to the GitHub CVE Issue Discussion and the VulDB Entry #329902.

Detection Methods for CVE-2025-12232

Indicators of Compromise

• Unusual HTTP POST requests to /goform/SafeClientFilter with abnormally large page parameter values
• Unexpected device reboots or crashes that may indicate exploitation attempts
• Anomalous network traffic patterns originating from or destined to the router's management interface
• Evidence of unauthorized configuration changes on the device

Detection Strategies

• Monitor network traffic for HTTP requests to /goform/SafeClientFilter endpoints with oversized parameters
• Implement intrusion detection rules to flag requests with page parameter values exceeding expected lengths
• Deploy web application firewall (WAF) rules to block malformed requests to Tenda device management interfaces
• Review device logs for repeated access attempts or error conditions related to client filtering functionality

Monitoring Recommendations

• Enable logging on network perimeter devices to capture traffic to IoT device management interfaces
• Implement network segmentation to isolate IoT devices from critical infrastructure
• Regularly audit devices for unexpected behavior or configuration changes
• Consider deploying network-based anomaly detection to identify exploitation attempts

How to Mitigate CVE-2025-12232

Immediate Actions Required

• Restrict network access to the Tenda CH22 management interface to trusted IP addresses only
• Disable remote management features if not required
• Place the device behind a firewall that blocks external access to the web interface
• Monitor the Tenda Official Website for firmware updates addressing this vulnerability

Patch Information

As of the last update on February 24, 2026, no official patch has been confirmed from Tenda for this vulnerability. Organizations should monitor vendor communications and apply firmware updates as soon as they become available. For the latest information, refer to the VulDB CTI Report #329902.

Workarounds

• Implement access control lists (ACLs) to restrict management interface access to specific trusted networks
• Use a VPN for remote administration instead of exposing the management interface directly
• Disable the web management interface entirely if administration can be performed through alternative methods
• Consider replacing affected devices with alternative hardware that has a better security track record

# Example: Restrict access to management interface via upstream firewall
# Block external access to the device's web interface (adjust IP as needed)
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP

# Allow access only from trusted management network
iptables -I FORWARD -s 10.0.0.0/24 -d 192.168.1.1 -p tcp --dport 80 -j ACCEPT