CVE-2026-2904: UTT 810G Firmware Buffer Overflow Flaw

CVE-2026-2904 Overview

A critical buffer overflow vulnerability has been identified in the UTT HiPER 810G router firmware version 1.7.7-171114. This vulnerability affects the strcpy function within the /goform/ConfigExceptAli endpoint, allowing remote attackers to exploit improper buffer handling to achieve remote code execution or cause system instability. The exploit has been publicly disclosed, increasing the urgency for affected organizations to implement protective measures.

Critical Impact

Remote attackers can exploit this buffer overflow vulnerability over the network to potentially execute arbitrary code or crash the device, compromising network infrastructure security.

Affected Products

• UTT HiPER 810G Firmware version 1.7.7-171114
• UTT 810G Hardware revision 3.0

Discovery Timeline

• 2026-02-22 - CVE-2026-2904 published to NVD
• 2026-02-24 - Last updated in NVD database

Technical Details for CVE-2026-2904

Vulnerability Analysis

This vulnerability stems from improper input validation in the UTT HiPER 810G router's web management interface. The /goform/ConfigExceptAli endpoint contains a classic buffer overflow condition where the strcpy function copies user-supplied input into a fixed-size buffer without proper bounds checking. Since strcpy does not verify the length of the source string before copying, an attacker can submit an oversized payload that overwrites adjacent memory regions.

The 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), both of which are fundamental memory safety issues commonly found in embedded device firmware written in C/C++.

Root Cause

The root cause of this vulnerability is the unsafe use of the strcpy function to handle user-controlled input in the /goform/ConfigExceptAli form handler. The function copies data from an HTTP request parameter directly into a stack or heap buffer without validating that the input length does not exceed the destination buffer's capacity. This allows an attacker to overflow the buffer and potentially overwrite critical memory structures such as return addresses or function pointers.

Attack Vector

The attack can be launched remotely over the network without requiring physical access to the device. An authenticated attacker with low privileges can send a specially crafted HTTP request to the /goform/ConfigExceptAli endpoint containing an oversized parameter value. When the vulnerable strcpy function processes this input, the buffer overflow occurs, potentially allowing the attacker to:

1. Crash the device, causing a denial of service
2. Overwrite return addresses to redirect execution flow
3. Execute arbitrary code with the privileges of the web server process

The vulnerability affects the router's web-based management interface, making any device with this interface exposed to the network a potential target. Given that the exploit has been publicly disclosed, the risk of active exploitation is elevated.

Detection Methods for CVE-2026-2904

Indicators of Compromise

• Unusually long HTTP POST requests targeting /goform/ConfigExceptAli
• Router crashes or unexpected reboots following web interface access
• Abnormal memory consumption patterns on the affected device
• Unexpected configuration changes or unauthorized administrative access

Detection Strategies

• Monitor HTTP traffic for oversized parameters in requests to /goform/ConfigExceptAli
• Implement network intrusion detection rules to flag buffer overflow attack patterns against UTT devices
• Review router logs for repeated crash events or watchdog timer triggers
• Deploy web application firewall (WAF) rules to block excessively long input strings

Monitoring Recommendations

• Enable logging on network firewalls to capture traffic destined for UTT router management interfaces
• Set up alerts for device availability issues that could indicate exploitation attempts
• Monitor for unauthorized firmware modifications or configuration changes
• Regularly audit network device access logs for suspicious authentication patterns

How to Mitigate CVE-2026-2904

Immediate Actions Required

• Restrict access to the router's web management interface to trusted internal networks only
• Implement network segmentation to isolate vulnerable devices from untrusted network segments
• Apply access control lists (ACLs) to limit which IP addresses can reach the management interface
• Consider disabling the web management interface entirely if not required for operations

Patch Information

At the time of publication, no vendor patch has been confirmed for this vulnerability. Organizations should monitor UTT's official channels and security advisories for firmware updates. For additional technical details, refer to the VulDB Advisory and the Ricky Place Vulnerability Analysis.

Workarounds

• Disable remote management access and allow only local console administration
• Place the device behind a VPN to restrict management access to authorized personnel
• Implement strong authentication and limit the number of accounts with administrative privileges
• Consider replacing the vulnerable device with a supported alternative if no patch becomes available

# Example: Restrict management interface access via firewall rules
# Block external access to the router management port (adjust IP and port as needed)
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP