CVE-2026-31058: UTT HiPER 1200GW DoS Vulnerability

CVE-2026-31058 Overview

A buffer overflow vulnerability has been discovered in the UTT Aggressive HiPER 1200GW router firmware version v2.5.3-170306. The vulnerability exists within the formConfigDnsFilterGlobal function, specifically in the handling of the timeRangeName parameter. Attackers can exploit this flaw to cause a Denial of Service (DoS) condition on affected devices by sending crafted input that overflows the vulnerable buffer.

Critical Impact

This buffer overflow vulnerability (CWE-120) can be exploited by an attacker on an adjacent network with high-level privileges to crash the affected router, causing network service disruption for connected devices.

Affected Products

• UTT Aggressive HiPER 1200GW v2.5.3-170306

Discovery Timeline

• 2026-04-06 - CVE CVE-2026-31058 published to NVD
• 2026-04-07 - Last updated in NVD database

Technical Details for CVE-2026-31058

Vulnerability Analysis

This vulnerability is classified as a classic buffer overflow (CWE-120: Buffer Copy without Checking Size of Input). The formConfigDnsFilterGlobal function in the UTT Aggressive HiPER 1200GW firmware does not properly validate the length of user-supplied input for the timeRangeName parameter before copying it into a fixed-size buffer.

When an attacker provides an excessively long string for the timeRangeName parameter, the data overflows beyond the allocated buffer boundaries, corrupting adjacent memory. This memory corruption leads to device instability and ultimately results in a denial of service condition where the router becomes unresponsive or crashes.

The vulnerability requires an attacker to have access to the adjacent network (such as being connected to the same local network segment) and high-level privileges (administrative access to the router's web interface). While this limits the attack surface, administrators should be aware that compromised internal networks or malicious insiders could leverage this vulnerability to disrupt network services.

Root Cause

The root cause of this vulnerability is improper input validation in the formConfigDnsFilterGlobal function. The function fails to verify the size of the timeRangeName parameter before performing a buffer copy operation. This is a classic example of unsafe memory handling where user-controlled input is copied into a fixed-size buffer without bounds checking, leading to a buffer overflow condition.

Attack Vector

The attack vector for CVE-2026-31058 is through an adjacent network, meaning the attacker must be on the same network segment as the vulnerable device. The attacker would need to authenticate to the device's management interface with administrative privileges and then submit a maliciously crafted request containing an oversized timeRangeName parameter to the DNS filter configuration endpoint. The crafted input would trigger the buffer overflow in the formConfigDnsFilterGlobal function, causing memory corruption and subsequent device crash.

The attack is executed by sending a specially crafted HTTP request to the router's web management interface with an excessively long string in the timeRangeName parameter field. Technical details and proof-of-concept information are available in the GitHub Vulnerability Report.

Detection Methods for CVE-2026-31058

Indicators of Compromise

• Unexpected router reboots or unresponsive device behavior
• HTTP requests to DNS filter configuration endpoints with unusually long parameter values
• Anomalous POST requests to formConfigDnsFilterGlobal with oversized timeRangeName parameters
• Network connectivity disruptions correlating with administrative interface access attempts

Detection Strategies

• Monitor HTTP traffic to the router's management interface for requests with abnormally large parameter values
• Implement web application firewall rules to detect and block oversized input in form parameters
• Configure network intrusion detection systems to alert on patterns matching buffer overflow exploitation attempts against embedded device management interfaces
• Review router access logs for suspicious administrative activity patterns

Monitoring Recommendations

• Enable logging on the UTT Aggressive HiPER 1200GW management interface and forward logs to a centralized SIEM
• Set up availability monitoring to detect unexpected device reboots or unresponsive states
• Monitor network segment traffic for anomalous patterns targeting router management ports
• Implement alerting for repeated failed or successful administrative authentication attempts

How to Mitigate CVE-2026-31058

Immediate Actions Required

• Restrict access to the router's web management interface to trusted administrators only
• Implement network segmentation to limit adjacent network access to the device
• Apply IP-based access control lists to the management interface
• Consider disabling remote management features if not required

Patch Information

At the time of this publication, no vendor patch information is available in the NVD data. System administrators should monitor UTT's official support channels for firmware updates addressing this vulnerability. Additional technical details are available in the GitHub Vulnerability Report.

Workarounds

• Restrict management interface access to specific IP addresses or VLANs
• Implement strong authentication and limit the number of administrative accounts
• Place the router behind a network firewall that can filter and inspect HTTP traffic
• If possible, disable the DNS filter configuration functionality until a patch is available
• Monitor the device closely for signs of exploitation or unexpected behavior

# Configuration example - Restrict management access (example ACL configuration)
# Note: Actual commands vary by device interface
# Limit management access to specific trusted IP addresses
# Configure on upstream firewall or network infrastructure
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