CVE-2026-9627: UTT HiPER 1200GW Buffer Overflow Flaw

CVE-2026-9627 Overview

CVE-2026-9627 is a buffer overflow vulnerability in the UTT HiPER 1200GW router through firmware version 2.5.3-170306. The flaw resides in the strcpy function within the /goform/setSysAdm endpoint of the Web Management Interface. Attackers can trigger the overflow by manipulating the sysAdmUser or sysAdmPass parameters. The issue is classified under [CWE-119] (improper restriction of operations within the bounds of a memory buffer). The exploit has been publicly released, increasing the likelihood of opportunistic attacks against exposed devices.

Critical Impact

Remote authenticated attackers can corrupt memory in the router's web management process, leading to denial of service or potential code execution on the device.

Affected Products

• UTT HiPER 1200GW router firmware up to and including version 2.5.3-170306
• Web Management Interface component (/goform/setSysAdm handler)
• Deployments exposing the administrative web interface to untrusted networks

Discovery Timeline

• 2026-05-27 - CVE-2026-9627 published to the National Vulnerability Database (NVD)
• 2026-05-27 - Last updated in NVD database

Technical Details for CVE-2026-9627

Vulnerability Analysis

The vulnerability is a classic stack-based buffer overflow caused by unsafe string handling in the device's HTTP request processing logic. When the Web Management Interface processes a POST request to /goform/setSysAdm, the firmware copies user-supplied values from the sysAdmUser and sysAdmPass parameters into fixed-size buffers using strcpy. Because strcpy performs no length validation, oversized input writes past the destination buffer and corrupts adjacent memory.

The attack requires network access to the management interface and low-privileged authentication, but no user interaction. Successful exploitation can crash the router or, depending on memory layout and mitigations, redirect execution flow on the embedded MIPS or ARM processor commonly used in HiPER hardware.

Root Cause

The root cause is the use of unbounded strcpy calls on attacker-controlled HTTP form fields. The handler trusts the length of sysAdmUser and sysAdmPass rather than enforcing input limits before copying data into stack-allocated buffers. Embedded routers of this class frequently lack stack canaries, address space layout randomization (ASLR), and non-executable stack protections, which raises the practical impact of the overflow.

Attack Vector

An attacker with credentials to the Web Management Interface, or access to a session where authentication can be reached, sends a crafted HTTP POST request to /goform/setSysAdm containing an oversized sysAdmUser or sysAdmPass value. The malformed request triggers the overflow during request parsing. Public proof-of-concept material is referenced in the GitHub CVE Documentation and the VulDB entry #365683.

No verified exploit code is reproduced here. Refer to the linked advisories for technical reproduction details.

Detection Methods for CVE-2026-9627

Indicators of Compromise

• HTTP POST requests to /goform/setSysAdm containing abnormally long sysAdmUser or sysAdmPass parameter values
• Unexpected reboots, watchdog resets, or crashes of the HiPER 1200GW web service
• Configuration changes to administrator credentials originating from unfamiliar source addresses
• Outbound connections from the router to unknown hosts following management interface activity

Detection Strategies

• Inspect web server and management logs for malformed or oversized form submissions to the setSysAdm handler
• Deploy network intrusion detection signatures that flag POST bodies exceeding expected length thresholds for router management endpoints
• Correlate router crash events with prior administrative HTTP traffic to identify exploitation attempts

Monitoring Recommendations

• Forward router syslog and HTTP access logs to a centralized log platform for retention and analysis
• Alert on management interface access from source addresses outside an approved administrative allowlist
• Track firmware version inventory to confirm whether HiPER 1200GW devices remain on vulnerable builds at or below 2.5.3-170306

How to Mitigate CVE-2026-9627

Immediate Actions Required

• Restrict access to the HiPER 1200GW Web Management Interface to trusted management VLANs or jump hosts
• Disable WAN-side administrative access and block inbound HTTP/HTTPS to the router from untrusted networks
• Rotate administrator credentials and review account lists for unauthorized additions
• Monitor the UTT vendor portal and VulDB #365683 for firmware updates addressing this issue

Patch Information

No vendor patch is referenced in the published advisory at the time of NVD publication on 2026-05-27. Operators should track vendor communications and apply firmware updates as soon as they are released. Until then, treat the management interface as exposed and apply compensating network controls.

Workarounds

• Place the router management interface behind a firewall rule that allows only specific administrator source IP addresses
• Require VPN access for any administrative session targeting the device
• Where feasible, replace affected devices with hardware that receives active security maintenance
• Audit administrator account usage and disable accounts that are not strictly required

# Example firewall restriction limiting access to the management interface
# Replace 192.0.2.10 with your administrator workstation address
iptables -A INPUT -p tcp --dport 80  -s 192.0.2.10 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 192.0.2.10 -j ACCEPT
iptables -A INPUT -p tcp --dport 80  -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP