CVE-2026-2067: UTT 520W Firmware Buffer Overflow Flaw

CVE-2026-2067 Overview

A buffer overflow vulnerability has been identified in UTT 进取 520W router firmware version 1.7.7-180627. This vulnerability affects the strcpy function within the /goform/formTimeGroupConfig endpoint. Remote attackers can exploit this flaw by manipulating the year1 argument, leading to a buffer overflow condition that could allow unauthorized code execution or system compromise. The exploit has been publicly disclosed, and the vendor was contacted regarding this vulnerability but did not respond.

Critical Impact

Remote attackers with low privileges can exploit this buffer overflow vulnerability over the network to potentially achieve full system compromise, affecting confidentiality, integrity, and availability of the affected router.

Affected Products

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

Discovery Timeline

• February 6, 2026 - CVE-2026-2067 published to NVD
• February 10, 2026 - Last updated in NVD database

Technical Details for CVE-2026-2067

Vulnerability Analysis

This vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw exists in the web management interface of the UTT 520W router, specifically within the time group configuration handler. When processing user-supplied input through the year1 parameter, the application uses an unsafe strcpy function that does not perform proper bounds checking before copying data into a fixed-size buffer.

The vulnerability can be triggered remotely by an authenticated attacker with low-level privileges. When exploited successfully, the attacker can overflow the stack buffer, potentially overwriting return addresses or other critical memory structures, leading to arbitrary code execution with the privileges of the web server process.

Root Cause

The root cause of this vulnerability lies in the improper use of the strcpy function within the /goform/formTimeGroupConfig handler. The strcpy function is inherently unsafe as it copies data from a source buffer to a destination buffer without checking whether the destination buffer has sufficient space to accommodate the incoming data. When the year1 parameter contains data exceeding the expected buffer size, a classic stack-based buffer overflow occurs.

This represents a fundamental failure to implement proper input validation and boundary checking—a common vulnerability pattern in embedded systems and IoT device firmware where memory-safe programming practices are often overlooked due to resource constraints or legacy codebases.

Attack Vector

The attack vector is network-based, requiring the attacker to have network access to the router's web management interface. The exploitation requires low-level authentication privileges, making this vulnerability accessible to any authenticated user on the network.

An attacker would craft a malicious HTTP request to the /goform/formTimeGroupConfig endpoint with an oversized year1 parameter value designed to overflow the target buffer. The payload would typically include shellcode or return-oriented programming (ROP) gadgets to achieve code execution.

The vulnerability mechanism involves sending specially crafted input through the web form to trigger the buffer overflow condition. Technical details and proof-of-concept information can be found in the GitHub CVE Details and VulDB entry #344634.

Detection Methods for CVE-2026-2067

Indicators of Compromise

• Unusual HTTP POST requests to /goform/formTimeGroupConfig with abnormally large year1 parameter values
• Unexpected process crashes or restarts of the web server on affected UTT routers
• Memory corruption artifacts or unexpected behavior in router logs
• Network traffic patterns indicating exploitation attempts against the router management interface

Detection Strategies

• Monitor HTTP traffic to UTT 520W routers for POST requests containing oversized parameters in form submissions to /goform/formTimeGroupConfig
• Implement intrusion detection rules to flag requests with year1 parameter values exceeding normal date ranges or expected string lengths
• Deploy network-based anomaly detection to identify buffer overflow exploitation attempts targeting embedded device web interfaces
• Review web server access logs for patterns consistent with buffer overflow fuzzing or exploitation

Monitoring Recommendations

• Enable comprehensive logging on the router management interface and forward logs to a centralized SIEM solution
• Implement network segmentation to restrict access to router management interfaces from untrusted networks
• Deploy SentinelOne Singularity for network visibility to detect and respond to exploitation attempts targeting IoT and embedded devices
• Establish baseline normal traffic patterns to identify anomalous requests that may indicate active exploitation

How to Mitigate CVE-2026-2067

Immediate Actions Required

• Restrict access to the router's web management interface to trusted administrator IP addresses only
• Implement network-level access controls to prevent untrusted users from reaching the /goform/formTimeGroupConfig endpoint
• Consider disabling the web management interface entirely if not required for operations
• Monitor for any signs of exploitation while awaiting vendor response or considering device replacement

Patch Information

The vendor (UTT) was contacted regarding this vulnerability but did not respond. As of the last update on February 10, 2026, no official patch has been released. Organizations using affected devices should implement the workarounds below and consider replacing vulnerable equipment with supported alternatives.

For the latest information, consult VulDB #344634 or the GitHub CVE documentation.

Workarounds

• Restrict management interface access to trusted IP addresses using firewall rules or router ACLs
• Place the router management interface on a dedicated management VLAN inaccessible from general user networks
• Implement a web application firewall (WAF) to filter malicious requests before they reach the vulnerable endpoint
• Consider replacing the affected device with a supported router that receives regular security updates

# Example firewall rule to restrict management access (iptables)
# Allow management access only from trusted admin subnet
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