CVE-2026-2981: UTT 810G Firmware Buffer Overflow Flaw

CVE-2026-2981 Overview

A buffer overflow vulnerability has been identified in UTT HiPER 810G routers running firmware versions up to 1.7.7-1711. The vulnerability exists within the strcpy function implementation in the /goform/formTaskEdit_ap file, where improper handling of the txtMin2 argument enables memory corruption through buffer overflow. This network-accessible vulnerability allows authenticated remote attackers to potentially execute arbitrary code or cause denial of service conditions on affected devices.

Critical Impact

Remote authenticated attackers can exploit this buffer overflow vulnerability to achieve high-impact compromise of confidentiality, integrity, and availability on affected UTT HiPER 810G network devices. The exploit has been publicly disclosed.

Affected Products

• UTT HiPER 810G Firmware versions up to 1.7.7-1711
• UTT HiPER 810G Hardware revision 3.0

Discovery Timeline

• 2026-02-23 - CVE-2026-2981 published to NVD
• 2026-02-24 - Last updated in NVD database

Technical Details for CVE-2026-2981

Vulnerability Analysis

This vulnerability stems from improper restriction of operations within the bounds of a memory buffer (CWE-119). The affected component is the task editing functionality accessible via the /goform/formTaskEdit_ap endpoint on UTT HiPER 810G routers. When processing the txtMin2 parameter, the firmware uses the unsafe strcpy function without proper bounds checking, allowing an attacker to supply an oversized input that overflows the destination buffer.

The vulnerability is remotely exploitable over the network and requires low attack complexity. While authentication is required (low privileges), no user interaction is needed. Successful exploitation can result in complete compromise of the device's confidentiality, integrity, and availability. The exploit code has been made publicly available, increasing the risk of active exploitation.

Root Cause

The root cause of this vulnerability is the use of the inherently unsafe strcpy function to copy user-controlled input from the txtMin2 parameter into a fixed-size buffer. 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's size. When an attacker supplies input longer than the allocated buffer space, the excess data overwrites adjacent memory regions, potentially corrupting critical data structures, return addresses, or function pointers.

Attack Vector

The attack vector for CVE-2026-2981 is network-based, targeting the web management interface of affected UTT HiPER 810G routers. An authenticated attacker can craft a malicious HTTP request to the /goform/formTaskEdit_ap endpoint containing an oversized value for the txtMin2 parameter. The attack flow proceeds as follows:

1. The attacker authenticates to the device's web management interface
2. A crafted HTTP request is sent to /goform/formTaskEdit_ap with a maliciously long txtMin2 parameter
3. The vulnerable strcpy function copies the oversized input without bounds validation
4. The buffer overflow corrupts adjacent memory, potentially allowing code execution or causing device crash

For detailed technical analysis and proof-of-concept information, refer to the GitHub CVE Vulnerability Report and VulDB #347365 Details.

Detection Methods for CVE-2026-2981

Indicators of Compromise

• Unusual HTTP POST requests to /goform/formTaskEdit_ap with abnormally long txtMin2 parameter values
• Unexpected device reboots or crashes that may indicate exploitation attempts
• Anomalous outbound network connections from the router device
• Memory corruption errors or unexpected behavior in device logs

Detection Strategies

• Implement web application firewall rules to detect and block HTTP requests with oversized parameters to /goform/formTaskEdit_ap
• Monitor network traffic for suspicious patterns targeting UTT HiPER 810G management interfaces
• Deploy intrusion detection signatures to identify buffer overflow exploitation attempts against this endpoint
• Review access logs for repeated authentication attempts followed by requests to the vulnerable endpoint

Monitoring Recommendations

• Enable comprehensive logging on UTT HiPER 810G devices and forward logs to a centralized SIEM solution
• Monitor for unexpected administrative access or configuration changes on affected devices
• Implement network segmentation to restrict access to device management interfaces from untrusted networks
• Set up alerts for any access attempts to /goform/formTaskEdit_ap from non-administrative IP addresses

How to Mitigate CVE-2026-2981

Immediate Actions Required

• Restrict network access to the UTT HiPER 810G web management interface to trusted IP addresses only
• Implement strong authentication and consider changing default credentials immediately
• Place affected devices behind a firewall that filters malicious requests to vulnerable endpoints
• Monitor vendor communications for firmware updates addressing this vulnerability

Patch Information

At the time of publication, no official patch has been released by UTT to address CVE-2026-2981. Organizations should monitor the VulDB #347365 Incident Report and UTT's official channels for security updates. Given the public disclosure of exploitation techniques, immediate implementation of compensating controls is strongly recommended.

Workarounds

• Disable remote administration access to the UTT HiPER 810G web interface when not required
• Implement network access control lists (ACLs) to limit management interface access to specific trusted IP addresses
• Deploy a reverse proxy or web application firewall in front of the device to filter oversized parameter values
• Consider replacing affected devices with alternative networking equipment if the vendor does not provide timely patches

# Example firewall rule to restrict access to management interface
# Block external access to vulnerable endpoint
iptables -A INPUT -p tcp --dport 80 -d <router_ip> -s ! <trusted_admin_ip> -j DROP
iptables -A INPUT -p tcp --dport 443 -d <router_ip> -s ! <trusted_admin_ip> -j DROP