CVE-2026-5152: Tenda CH22 Buffer Overflow Vulnerability

CVE-2026-5152 Overview

A stack-based buffer overflow vulnerability has been identified in Tenda CH22 firmware version 1.0.0.1. The vulnerability exists in the formCreateFileName function within the /goform/createFileName endpoint. By manipulating the fileNameMit argument, an attacker can trigger a stack-based buffer overflow condition. This vulnerability can be exploited remotely over the network, and a public exploit is reportedly available.

Critical Impact

Remote attackers can exploit this buffer overflow vulnerability to potentially achieve code execution on affected Tenda CH22 devices, compromising network infrastructure security.

Affected Products

• Tenda CH22 Firmware version 1.0.0.1
• Tenda CH22 Hardware

Discovery Timeline

• 2026-03-30 - CVE-2026-5152 published to NVD
• 2026-04-02 - Last updated in NVD database

Technical Details for CVE-2026-5152

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-787 (Out-of-bounds Write). The flaw resides in how the formCreateFileName function processes user-supplied input through the fileNameMit parameter.

When a malicious request is sent to the /goform/createFileName endpoint with a specially crafted fileNameMit value, the function fails to properly validate the length of the input before copying it to a fixed-size stack buffer. This lack of bounds checking allows an attacker to write data beyond the allocated buffer boundaries, corrupting adjacent stack memory.

The network-accessible nature of this vulnerability significantly increases its risk profile, as it can be exploited without physical access to the device. Successful exploitation could allow an attacker to overwrite the return address on the stack, potentially redirecting program execution to attacker-controlled code.

Root Cause

The root cause of this vulnerability is insufficient input validation in the formCreateFileName function. The function accepts user-controlled data through the fileNameMit parameter and copies it to a stack-allocated buffer without verifying that the input length does not exceed the buffer's capacity. This classic buffer overflow pattern allows attackers to corrupt stack memory when providing oversized input.

Attack Vector

The attack can be initiated remotely over the network by sending a malicious HTTP request to the vulnerable endpoint. An attacker with low-level privileges can craft a request targeting /goform/createFileName with an excessively long fileNameMit parameter value. The vulnerable function processes this input without proper bounds checking, resulting in a stack-based buffer overflow that corrupts adjacent memory on the stack.

The vulnerability is exploited by sending specially crafted POST requests to the /goform/createFileName endpoint. When the fileNameMit parameter contains data exceeding the expected buffer size, the overflow occurs, potentially allowing control over the program's execution flow. Technical details can be found in the GitHub Vulnerability Information and VulDB Entry.

Detection Methods for CVE-2026-5152

Indicators of Compromise

• Unusual or excessively long HTTP POST requests targeting /goform/createFileName
• Unexpected device reboots or service crashes on Tenda CH22 devices
• Anomalous network traffic patterns originating from or targeting the device's web management interface
• Evidence of unauthorized configuration changes on affected devices

Detection Strategies

• Implement network intrusion detection rules to identify POST requests to /goform/createFileName with abnormally large fileNameMit parameter values
• Monitor web server logs on Tenda CH22 devices for suspicious requests targeting the vulnerable endpoint
• Deploy network behavior analysis to detect exploitation attempts characterized by malformed HTTP requests
• Use SentinelOne Singularity to monitor for anomalous process behavior on network segments containing affected devices

Monitoring Recommendations

• Configure alerts for any access attempts to the /goform/createFileName endpoint from untrusted network sources
• Establish baseline network behavior for Tenda CH22 devices and alert on deviations
• Monitor for signs of device compromise such as unexpected outbound connections or configuration modifications
• Implement centralized logging for all HTTP requests to device management interfaces

How to Mitigate CVE-2026-5152

Immediate Actions Required

• Restrict network access to the Tenda CH22 web management interface to trusted IP addresses only
• Place affected devices behind a firewall and disable remote management access from the internet
• Implement network segmentation to isolate vulnerable devices from critical network assets
• Monitor affected devices for signs of exploitation while awaiting a vendor patch

Patch Information

At the time of this writing, no official patch has been released by Tenda for this vulnerability. Organizations should monitor the Tenda Official Website for security updates and firmware releases. Check the VulDB Entry for the latest vulnerability status and any vendor response information.

Workarounds

• Disable remote management access to the device's web interface if not required for operations
• Implement strict firewall rules to block external access to the /goform/ directory and web management ports
• Use VPN or other secure tunneling methods if remote administration is necessary
• Consider replacing affected devices with alternatives that receive regular security updates if no patch is forthcoming

# Example firewall rule to restrict access to device management interface
# Block external access to Tenda CH22 web interface (adjust IP/port as needed)
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