CVE-2026-76003: UTT HiPER 1200GW Buffer Overflow Flaw

CVE-2026-76003 Overview

CVE-2026-76003 is a stack-based buffer overflow vulnerability [CWE-119] affecting UTT HiPER 1200GW routers through firmware version 2.5.3-170306. The flaw resides in the strcpy operation within the /goform/formGroupConfig handler. Attackers can manipulate the timestart argument to overflow a fixed-size stack buffer. The attack is executable over the network and requires only low-privilege access. A public exploit has been released, increasing the likelihood of opportunistic attacks against exposed devices.

Critical Impact
Remote attackers with low privileges can trigger a stack-based buffer overflow through the timestart parameter, potentially leading to arbitrary code execution or device compromise on UTT HiPER 1200GW routers.

Affected Products

UTT HiPER 1200GW router
Firmware versions up to and including 2.5.3-170306
The /goform/formGroupConfig web management endpoint

Discovery Timeline

2026-08-19 - CVE-2026-76003 published to NVD
2026-08-20 - Last updated in NVD database

Technical Details for CVE-2026-76003

Vulnerability Analysis

The vulnerability exists in the formGroupConfig handler within the router's web management interface. The handler processes HTTP requests to /goform/formGroupConfig and copies the user-supplied timestart parameter into a fixed-size stack buffer using strcpy. Because strcpy performs no bounds checking, an oversized timestart value overwrites adjacent stack memory, including the saved return address.

An authenticated attacker sending a crafted POST request can corrupt the stack frame of the handling function. On MIPS-based embedded devices such as the HiPER 1200GW, overwriting the return address allows redirection of execution flow to attacker-controlled data. Successful exploitation can yield arbitrary code execution in the context of the web server process, typically running with elevated privileges on consumer and small-business router firmware.

Root Cause

The root cause is unsafe use of the strcpy C library function on network-supplied input without validating the length of the source string. The timestart argument accepted by formGroupConfig is not sanitized or truncated before being copied into a stack-allocated buffer. This pattern is a classic instance of [CWE-119] improper restriction of operations within the bounds of a memory buffer.

Attack Vector

Exploitation requires network reachability to the router's HTTP management interface and low-level authenticated access. The attacker submits a POST request to /goform/formGroupConfig containing an overlong timestart value. Public proof-of-concept material is available in the referenced GitHub CVE Vulnerability Details repository, which lowers the barrier for weaponization.

Refer to the VulDB CVE Report for additional technical context on the exploitation path.

Detection Methods for CVE-2026-76003

Indicators of Compromise

HTTP POST requests to /goform/formGroupConfig containing unusually long timestart parameter values
Web management interface crashes, reboots, or watchdog resets on UTT HiPER 1200GW devices
Unexpected outbound connections from the router to unknown hosts following management-interface activity
Anomalous configuration changes on the router without corresponding administrative activity

Detection Strategies

Inspect HTTP request logs on the router or upstream proxy for timestart parameter values exceeding expected timestamp lengths
Deploy network intrusion detection signatures that flag oversized POST bodies targeting /goform/formGroupConfig
Correlate router crash telemetry with recent inbound HTTP requests to the management interface

Monitoring Recommendations

Restrict and monitor administrative access to the router web interface, alerting on any external connections
Baseline management-interface traffic volumes and alert on spikes consistent with brute-force or fuzzing
Log authentication events on the router and forward them to a centralized logging platform for review

How to Mitigate CVE-2026-76003

Immediate Actions Required

Disable remote WAN-side administration on the UTT HiPER 1200GW immediately
Restrict LAN-side access to the router management interface to a small set of trusted administrative hosts
Rotate all administrative credentials on the device to invalidate any previously compromised sessions
Inventory all UTT HiPER 1200GW devices in the environment and verify their firmware version

Patch Information

No vendor advisory or fixed firmware version is listed in the referenced sources at the time of publication. Consult the VulDB Vulnerability Overview and monitor UTT's official channels for a firmware update addressing the formGroupConfig handler. Until a patch is available, apply the compensating controls listed below.

Workarounds

Place the router management interface behind a VPN or management VLAN that is unreachable from untrusted networks
Block inbound traffic to the router's HTTP administration port from the WAN at any upstream firewall
Consider replacing end-of-life UTT HiPER 1200GW devices with actively supported hardware if no vendor patch materializes

bash

# Example: block external access to the router HTTP admin interface at an upstream firewall
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -i <wan_interface> -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -i <wan_interface> -j DROP