CVE-2025-7117: UTT HiPER 840G Buffer Overflow Vulnerability

CVE-2025-7117 Overview

CVE-2025-7117 is a buffer overflow vulnerability in the UTT HiPER 840G router firmware through version 3.1.1-190328. The flaw resides in the /goform/websWhiteList handler, where the addHostFilter argument is processed without proper bounds checking [CWE-119]. Remote attackers with low privileges can trigger memory corruption over the network. Public disclosure includes proof-of-concept details, raising the likelihood of exploitation attempts against exposed devices. The vendor was contacted prior to publication but did not respond, leaving deployed devices without an official patch.

Critical Impact
Authenticated remote attackers can corrupt router memory through the addHostFilter parameter, potentially achieving arbitrary code execution on affected UTT HiPER 840G devices.

Affected Products

UTT HiPER 840G hardware (version 3.0)
UTT HiPER 840G firmware up to 3.1.1-190328
Deployments exposing the web management interface (/goform/websWhiteList) to untrusted networks

Discovery Timeline

2025-07-07 - CVE-2025-7117 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-7117

Vulnerability Analysis

The vulnerability affects the web management interface of the UTT HiPER 840G router. The endpoint /goform/websWhiteList accepts the addHostFilter parameter from authenticated users and copies the supplied value into a fixed-size buffer without validating the input length. Supplying an oversized value overflows the destination buffer and corrupts adjacent memory, including saved return addresses on stack-based implementations common to embedded MIPS and ARM routers. Successful exploitation can crash the router or hijack control flow, enabling code execution under the privileges of the web server process. According to the CVE record, the issue requires only low-level privileges (PR:L) and no user interaction.

Root Cause

The root cause is improper restriction of operations within the bounds of a memory buffer [CWE-119]. The handler for addHostFilter performs an unbounded copy operation, lacking a length check or use of a size-limited copy primitive such as strncpy with a verified destination size. This pattern is common in legacy goform CGI handlers compiled into the router's HTTP daemon.

Attack Vector

An attacker reaches the vulnerable endpoint over the network by sending a crafted HTTP request to /goform/websWhiteList containing an oversized addHostFilter value. The attacker must hold valid credentials to authenticate to the management interface. Where the web UI is exposed to the WAN or to a flat internal network, the attack surface expands significantly. Public proof-of-concept material referenced in the GitHub CVE Documentation describes the request structure required to trigger the overflow.

No verified exploit code is reproduced here; refer to the VulDB entry #315028 for additional technical context.

Detection Methods for CVE-2025-7117

Indicators of Compromise

HTTP POST requests to /goform/websWhiteList containing unusually long addHostFilter parameter values
Unexpected reboots, watchdog resets, or httpd process crashes recorded in router system logs
New or unexplained firewall whitelist entries appearing in the host filter configuration
Outbound connections from the router management plane to unfamiliar external hosts

Detection Strategies

Inspect web server and reverse proxy logs for POST requests to /goform/websWhiteList where the addHostFilter parameter exceeds expected hostname lengths (e.g., over 256 bytes)
Deploy network IDS signatures that flag HTTP requests to UTT goform endpoints containing non-printable bytes or shellcode-like payloads in form parameters
Correlate authentication events to the router admin interface with subsequent crash or restart events on the same device

Monitoring Recommendations

Forward router syslog output to a central log platform and alert on repeated httpd segmentation faults or kernel oops messages
Monitor management interface access from non-administrative source IPs and alert on any WAN-side authentication attempts
Track configuration drift on host filter and whitelist tables to detect unauthorized modifications

How to Mitigate CVE-2025-7117

Immediate Actions Required

Restrict access to the router web management interface to trusted administrative networks only, blocking WAN-side exposure entirely
Rotate administrative credentials on all UTT HiPER 840G devices to reduce the risk of authenticated exploitation
Place vulnerable devices behind a network segmentation boundary that filters HTTP traffic to /goform/* endpoints from untrusted sources
Evaluate replacement of end-of-support UTT devices given the vendor's lack of response to disclosure

Patch Information

No vendor patch is available at the time of publication. The original disclosure notes that UTT was contacted but did not respond. Administrators should consult the GitHub CVE Documentation and VulDB submission #605864 for ongoing updates, and contact UTT directly to request fixed firmware.

Workarounds

Disable remote administration over the WAN interface and confine management traffic to a dedicated VLAN
Apply ACLs at upstream firewalls to block inbound HTTP and HTTPS requests destined for the router management port
Require VPN-only access to the management plane and enforce multi-factor authentication on the jump host used for administration
Replace the device with a vendor-supported router platform where business requirements permit

bash

# Example ACL restricting management access to a trusted admin subnet
iptables -A INPUT -p tcp --dport 80 -s 10.10.50.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -s 10.10.50.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP