CVE-2025-12272: Tenda CH22 Buffer Overflow Vulnerability

CVE-2025-12272 Overview

A buffer overflow vulnerability has been discovered in the Tenda CH22 router firmware version 1.0.0.1. This security flaw impacts the fromAddressNat function within the /goform/addressNat endpoint. By manipulating the page argument, an attacker can trigger a buffer overflow condition. The vulnerability can be exploited remotely over the network, making it particularly dangerous for exposed devices. The exploit has been publicly released, increasing the risk of active exploitation.

Critical Impact

Remote attackers can exploit this buffer overflow vulnerability to potentially execute arbitrary code, cause denial of service, or compromise the confidentiality, integrity, and availability of affected Tenda CH22 routers.

Affected Products

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

Discovery Timeline

• October 27, 2025 - CVE-2025-12272 published to NVD
• February 24, 2026 - Last updated in NVD database

Technical Details for CVE-2025-12272

Vulnerability Analysis

This vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw exists in the fromAddressNat function which handles form submissions at the /goform/addressNat web endpoint on the Tenda CH22 router. When processing the page parameter, the function fails to properly validate input boundaries before copying data into a fixed-size buffer, resulting in a classic buffer overflow condition.

The network-accessible nature of this vulnerability means that any attacker who can reach the router's web management interface can potentially exploit this flaw. Since the exploit has been publicly disclosed, the window for attacks against unpatched devices is considerably widened.

Root Cause

The root cause stems from improper bounds checking in the fromAddressNat function when handling user-supplied input through the page argument. The function copies input data into a stack or heap buffer without verifying that the input length does not exceed the allocated buffer size, allowing attackers to overwrite adjacent memory regions.

Attack Vector

The attack vector is network-based, requiring low privileges to execute. An authenticated attacker with network access to the router's web management interface can craft a malicious HTTP request to the /goform/addressNat endpoint with an oversized page parameter. This triggers the buffer overflow, potentially allowing the attacker to:

• Overwrite return addresses to redirect execution flow
• Inject and execute arbitrary code with router privileges
• Cause a denial of service by crashing the device
• Compromise the confidentiality, integrity, and availability of the device

The vulnerability can be exploited by sending a crafted HTTP POST request to the affected endpoint with a specially constructed page parameter that exceeds expected bounds. For detailed technical analysis, refer to the GitHub Issue for CVE-21 which contains additional vulnerability documentation.

Detection Methods for CVE-2025-12272

Indicators of Compromise

• Unexpected router reboots or crashes when accessing the web management interface
• Anomalous HTTP POST requests to /goform/addressNat with unusually large page parameter values
• Memory corruption indicators in router logs (if available)
• Unexpected changes to router configuration or firmware

Detection Strategies

• Monitor network traffic for HTTP requests targeting /goform/addressNat with oversized parameters
• Implement web application firewall (WAF) rules to detect and block requests with abnormally large input values
• Deploy network intrusion detection systems (IDS) with signatures for buffer overflow attack patterns
• Review access logs for repeated or suspicious requests to the affected endpoint

Monitoring Recommendations

• Enable logging on the router's web management interface if supported
• Monitor for unusual outbound connections from the router that may indicate compromise
• Implement network segmentation to limit exposure of router management interfaces
• Regularly audit network traffic patterns for anomalies targeting IoT and network infrastructure devices

How to Mitigate CVE-2025-12272

Immediate Actions Required

• Restrict access to the router's web management interface to trusted IP addresses only
• Disable remote management capabilities if not required
• Implement network segmentation to isolate the router from untrusted networks
• Monitor the Tenda Website for firmware updates addressing this vulnerability

Patch Information

As of the last update, no official patch information has been released by Tenda. Organizations should monitor the vendor's security advisories and update channels for firmware releases that address CVE-2025-12272. Additional technical details and tracking information can be found at VulDB #329944.

Workarounds

• Disable the web management interface entirely if not operationally required
• Implement strong firewall rules to block external access to port 80/443 on the router
• Use a VPN for remote administration instead of exposing the management interface directly
• Consider replacing the affected device with an alternative that receives regular security updates

# Example firewall rule to restrict management access (adjust to your firewall)
# Block external access to router management interface
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