CVE-2026-5566: UTT HiPER 1250GW Buffer Overflow Flaw

CVE-2026-5566 Overview

A buffer overflow vulnerability has been identified in UTT HiPER 1250GW wireless gateway devices running firmware versions up to 3.2.7-210907-180535. The vulnerability exists in the strcpy function within the /goform/formNatStaticMap endpoint. An attacker can exploit this flaw by manipulating the NatBind argument, causing a buffer overflow condition that can be triggered remotely over the network.

The exploit for this vulnerability is now publicly available, increasing the risk of exploitation in the wild. This is a classic example of unsafe string handling in embedded device firmware, where the use of strcpy without proper bounds checking allows attackers to overflow a buffer with user-controlled input.

Critical Impact

Remote attackers can exploit this buffer overflow to potentially achieve arbitrary code execution on affected UTT HiPER 1250GW devices, potentially compromising the entire network infrastructure protected by the gateway.

Affected Products

• UTT HiPER 1250GW firmware versions up to 3.2.7-210907-180535
• UTT HiPER 1250GW wireless gateway devices with vulnerable web management interface

Discovery Timeline

• 2026-04-05 - CVE-2026-5566 published to NVD
• 2026-04-07 - Last updated in NVD database

Technical Details for CVE-2026-5566

Vulnerability Analysis

This vulnerability falls under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The core issue stems from the use of the inherently unsafe strcpy function to handle user-supplied input from the NatBind parameter in the NAT static mapping form handler.

When a request is sent to /goform/formNatStaticMap, the firmware processes the NatBind argument without adequate validation of its length. The strcpy function copies the input string into a fixed-size buffer without checking boundaries, allowing an attacker to write beyond the allocated memory space.

The vulnerability is exploitable remotely with low attack complexity. An attacker requires low-level privileges to access the web management interface, but no user interaction is needed to trigger the exploit. Successful exploitation can lead to high impact on confidentiality, integrity, and availability of the affected system.

Root Cause

The root cause is the use of the unsafe strcpy function for handling user-controlled input in the /goform/formNatStaticMap endpoint. The strcpy function does not perform bounds checking, meaning it will continue copying data until it encounters a null terminator, regardless of the destination buffer size. This design flaw allows an attacker to provide an oversized NatBind parameter value that exceeds the allocated buffer, overwriting adjacent memory.

Modern secure coding practices mandate the use of safer alternatives such as strncpy or strlcpy with explicit length limits, or better yet, dynamically allocated buffers with proper size validation.

Attack Vector

The attack vector is network-based, targeting the web management interface of the UTT HiPER 1250GW device. An attacker can craft a malicious HTTP request to the /goform/formNatStaticMap endpoint with an oversized NatBind parameter value. The buffer overflow can potentially overwrite critical memory structures such as return addresses or function pointers, enabling arbitrary code execution.

The attack requires the attacker to have network access to the device's management interface. If the management interface is exposed to the internet or accessible from an untrusted network segment, the risk of exploitation increases significantly. Technical details and proof-of-concept information are available through the GitHub CVE Issue and VulDB Vulnerability Record.

Detection Methods for CVE-2026-5566

Indicators of Compromise

• Unusual HTTP POST requests to /goform/formNatStaticMap with abnormally long NatBind parameter values
• Device crashes, reboots, or unexpected behavior following web interface access
• Evidence of unauthorized configuration changes on the gateway device
• Anomalous network traffic patterns originating from or destined to the gateway management interface

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block HTTP requests with oversized parameter values targeting /goform/formNatStaticMap
• Deploy network intrusion detection systems (NIDS) with signatures for buffer overflow exploitation patterns in HTTP traffic
• Monitor device logs for repeated crashes or segmentation faults that may indicate exploitation attempts
• Use SentinelOne Singularity to detect anomalous process behavior and memory corruption attempts on network devices where agent deployment is possible

Monitoring Recommendations

• Enable verbose logging on the UTT HiPER 1250GW web management interface if supported
• Monitor network traffic to and from device management interfaces for suspicious patterns
• Implement network segmentation to isolate device management interfaces from untrusted networks
• Deploy honeypot devices with vulnerable firmware to detect active exploitation campaigns targeting this vulnerability

How to Mitigate CVE-2026-5566

Immediate Actions Required

• Restrict access to the web management interface to trusted IP addresses only using access control lists (ACLs)
• Disable remote management access if not required for operations
• Place the device management interface on a separate, isolated VLAN
• Monitor the UTT vendor website for firmware updates addressing this vulnerability
• Consider deploying a web application firewall in front of the management interface to filter malicious requests

Patch Information

At the time of publication, no official patch information has been released by UTT for this vulnerability. Organizations should monitor vendor channels for security updates and apply patches as soon as they become available. For additional technical details and threat intelligence, refer to the VulDB CTI Report and VulDB Submit Entry.

Workarounds

• Implement network access control to restrict web management interface access to specific trusted IP addresses
• Use a reverse proxy with request filtering to block requests containing oversized NatBind parameters
• Disable the NAT static mapping feature if not operationally required
• Consider replacing vulnerable devices with alternative solutions until a patch is available
• Deploy network monitoring to detect and alert on potential exploitation attempts

# Example: Restrict management interface access using firewall rules
# Block all external access to the web management port (adjust 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

# Alternative: Use IP whitelist on upstream firewall/router
# Only allow management access from administrative workstations