CVE-2026-2066: UTT 520W Buffer Overflow Vulnerability

CVE-2026-2066 Overview

A buffer overflow vulnerability has been identified in UTT 进取 520W firmware version 1.7.7-180627. This vulnerability affects the strcpy function within the file /goform/formIpGroupConfig, where improper handling of the groupName argument can lead to a buffer overflow condition. The attack can be initiated remotely by authenticated users, potentially allowing attackers to execute arbitrary code or cause denial of service on affected devices. The exploit has been made publicly available, increasing the risk of active exploitation. Notably, the vendor was contacted about this disclosure but did not respond.

Critical Impact

Remote attackers with low privileges can exploit this buffer overflow to achieve high impact on confidentiality, integrity, and availability of affected UTT 520W routers.

Affected Products

• UTT 520W Firmware version 1.7.7-180627
• UTT 520W Hardware version 3.0

Discovery Timeline

• 2026-02-06 - CVE-2026-2066 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2026-2066

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw exists in the IP Group Configuration functionality of the UTT 520W router's web management interface. When processing the groupName parameter in requests to /goform/formIpGroupConfig, the firmware uses the unsafe strcpy function without proper bounds checking. This allows an attacker to supply an overly long string that exceeds the allocated buffer size, resulting in adjacent memory being overwritten.

The network-accessible nature of this vulnerability combined with low attack complexity makes it particularly dangerous in environments where the router's management interface is exposed. Successful exploitation could allow attackers to hijack program execution flow, potentially leading to complete device compromise.

Root Cause

The root cause of this vulnerability is the use of the inherently unsafe strcpy function without implementing proper input length validation. The strcpy function copies characters from a source string to a destination buffer until it encounters a null terminator, without checking whether the destination buffer has sufficient space. When the groupName parameter contains more characters than the destination buffer can accommodate, memory corruption occurs.

Attack Vector

The attack is performed remotely over the network by sending a specially crafted HTTP request to the /goform/formIpGroupConfig endpoint. An authenticated attacker with low privileges can manipulate the groupName argument to include an excessively long string value. When the server processes this request, the strcpy function copies the malicious input without bounds checking, causing a buffer overflow that can overwrite critical memory structures such as return addresses or function pointers.

The vulnerability can be exploited through the router's web management interface. Technical details and proof-of-concept information are available through the GitHub CVE Documentation and VulDB #344633.

Detection Methods for CVE-2026-2066

Indicators of Compromise

• Anomalous HTTP POST requests to /goform/formIpGroupConfig containing unusually long groupName parameter values
• Router service crashes or unexpected reboots following web interface access
• Unusual network traffic patterns originating from the router management interface
• Modified router configurations or unauthorized administrative access

Detection Strategies

• Implement network intrusion detection rules to flag HTTP requests to /goform/formIpGroupConfig with groupName parameters exceeding normal length thresholds
• Monitor web server logs for repeated requests to the vulnerable endpoint with varying payload lengths, indicative of exploitation attempts
• Deploy anomaly detection for router process crashes or memory-related errors
• Use endpoint detection solutions capable of identifying buffer overflow exploitation patterns

Monitoring Recommendations

• Enable verbose logging on the UTT 520W router if supported to capture detailed request information
• Implement network segmentation to isolate router management interfaces from untrusted networks
• Configure SIEM alerts for any access attempts to the vulnerable form endpoint
• Regularly review router access logs for unauthorized authentication attempts

How to Mitigate CVE-2026-2066

Immediate Actions Required

• Restrict access to the router's web management interface to trusted IP addresses only
• Implement network-level access controls to prevent unauthorized access to /goform/formIpGroupConfig
• Consider placing the management interface behind a VPN or on an isolated management VLAN
• Disable remote management access if not required for operations
• Monitor for any signs of exploitation until a patch becomes available

Patch Information

At the time of disclosure, the vendor (UTT) was contacted but did not respond. No official patch is currently available for this vulnerability. Organizations should implement the recommended workarounds and monitor vendor communications for future security updates. Additional technical details can be found at VulDB Submission #745260.

Workarounds

• Implement strict access control lists (ACLs) to limit management interface access to specific trusted IP addresses or networks
• Deploy a web application firewall (WAF) to filter requests containing excessively long parameter values
• Consider replacing vulnerable devices with alternative networking equipment from vendors with active security response programs
• If possible, disable the IP Group Configuration feature until a fix is available

# Example: Restrict management interface access via firewall rules
# Block external access to router management port (example using iptables)
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP

# For HTTPS management (if applicable)
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP