CVE-2026-2086: UTT HiPER 810G Buffer Overflow Vulnerability

CVE-2026-2086 Overview

A buffer overflow vulnerability has been identified in the UTT HiPER 810G router affecting firmware versions up to 1.7.7-171114. The vulnerability exists in the strcpy function within the /goform/formFireWall endpoint of the Management Interface. By manipulating the GroupName argument, an attacker can trigger a buffer overflow condition that may lead to arbitrary code execution or denial of service.

Critical Impact
Remote attackers with low privileges can exploit this buffer overflow vulnerability over the network to potentially compromise device integrity, confidentiality, and availability. The exploit is publicly available, increasing the risk of active exploitation.

Affected Products

UTT HiPER 810G firmware versions up to 1.7.7-171114
UTT HiPER 810G Management Interface component
Devices with /goform/formFireWall endpoint accessible

Discovery Timeline

2026-02-07 - CVE CVE-2026-2086 published to NVD
2026-02-09 - Last updated in NVD database

Technical Details for CVE-2026-2086

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The core issue stems from the unsafe use of the strcpy function when processing user-supplied input from the GroupName parameter. When handling firewall configuration requests through the Management Interface, the application fails to properly validate the length of the input before copying it to a fixed-size buffer. This classic buffer overflow pattern allows attackers to overwrite adjacent memory regions, potentially corrupting return addresses, function pointers, or other critical data structures.

The attack can be launched remotely over the network and requires only low-privilege authentication to the Management Interface. No user interaction is required for exploitation, making this vulnerability particularly dangerous for devices exposed to untrusted networks.

Root Cause

The root cause of this vulnerability is the improper use of the strcpy function in the /goform/formFireWall handler. The strcpy function does not perform bounds checking and will copy data until it encounters a null terminator, regardless of the destination buffer's size. When the GroupName argument exceeds the allocated buffer size, the excess data overwrites adjacent memory, leading to memory corruption. This is a well-known vulnerability pattern that should be addressed by using safer string handling functions such as strncpy or strlcpy with proper length validation.

Attack Vector

The attack is conducted remotely over the network by sending a specially crafted HTTP request to the /goform/formFireWall endpoint on the Management Interface. The attacker must provide an overly long string in the GroupName parameter that exceeds the expected buffer size. Upon processing this malicious input, the vulnerable strcpy function will write beyond the allocated buffer boundaries.

A successful exploit could allow an attacker to:

Execute arbitrary code on the device with elevated privileges
Crash the device causing denial of service
Modify device configuration or firewall rules
Gain persistent access to the network infrastructure

The exploit for this vulnerability is publicly available, as noted in the GitHub CVE Issue Discussion. The vendor was contacted early about this disclosure but did not respond in any way.

Detection Methods for CVE-2026-2086

Indicators of Compromise

Unexpected crashes or reboots of UTT HiPER 810G devices
Anomalous HTTP POST requests to /goform/formFireWall with unusually long GroupName parameters
Suspicious network traffic patterns originating from or targeting the router's management interface
Modified firewall rules or device configurations without administrative authorization

Detection Strategies

Monitor HTTP requests to the Management Interface for abnormally long parameter values in form submissions
Implement network intrusion detection rules to identify buffer overflow exploitation attempts targeting /goform/formFireWall
Review device logs for segmentation faults, memory corruption errors, or unexpected process terminations
Deploy network traffic analysis to detect POST requests with excessive payload sizes to management endpoints

Monitoring Recommendations

Enable comprehensive logging on all UTT HiPER 810G devices and forward logs to a centralized SIEM solution
Implement alerting for any access attempts to the Management Interface from untrusted network segments
Monitor for unusual authentication patterns or failed login attempts followed by successful exploitation indicators
Regularly audit device configurations for unauthorized modifications

How to Mitigate CVE-2026-2086

Immediate Actions Required

Restrict access to the Management Interface to trusted internal networks only using firewall rules or ACLs
Disable remote management access from the WAN interface immediately
Implement network segmentation to isolate affected devices from critical network resources
Monitor for exploitation attempts using the detection strategies outlined above

Patch Information

As of the last update on 2026-02-09, no official patch has been released by the vendor. According to the vulnerability disclosure, the vendor was contacted early about this issue but did not respond. Organizations should implement workarounds and consider the long-term viability of continuing to use affected devices.

For additional technical details and updates, refer to:

Workarounds

Implement access control lists (ACLs) to restrict Management Interface access to specific trusted IP addresses only
Deploy a reverse proxy or web application firewall (WAF) in front of the Management Interface to filter malicious requests
Consider replacing affected devices with alternative hardware from vendors with better security response practices
If the Management Interface must remain accessible, implement strict input validation at the network perimeter level

bash

# Configuration example - Restrict management access via iptables on upstream firewall
# Block external access to management interface port (typically 80/443)
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 80 -j DROP
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 443 -j DROP

# Allow management access only from trusted admin subnet
iptables -I FORWARD -s 192.168.1.0/24 -d <ROUTER_IP> -p tcp --dport 80 -j ACCEPT
iptables -I FORWARD -s 192.168.1.0/24 -d <ROUTER_IP> -p tcp --dport 443 -j ACCEPT