CVE-2025-7570: UTT HiPER 840G Buffer Overflow Vulnerability

CVE-2025-7570 Overview

CVE-2025-7570 is a buffer overflow vulnerability affecting the UTT HiPER 840G router through firmware version 3.1.1-190328. The flaw resides in the /goform/aspRemoteApConfTempSend endpoint, where the remoteSrcTemp parameter is processed without proper bounds checking. An attacker with low privileges can send a crafted request over the network to trigger memory corruption, potentially leading to arbitrary code execution or device compromise. The exploit details have been disclosed publicly, increasing the risk of opportunistic attacks. The vendor was contacted by the reporter but did not respond, leaving affected devices without an official patch.

Critical Impact
Remote attackers can corrupt memory on UTT HiPER 840G routers through a single crafted HTTP request, with public exploit details available and no vendor patch.

Affected Products

UTT HiPER 840G router (hardware)
UTT 840G firmware versions up to and including 3.1.1-190328
Deployments exposing the web management interface (/goform/aspRemoteApConfTempSend)

Discovery Timeline

2025-07-14 - CVE-2025-7570 published to the National Vulnerability Database (NVD)
2026-01-08 - Last updated in NVD database

Technical Details for CVE-2025-7570

Vulnerability Analysis

The vulnerability is a classic buffer overflow [CWE-119] in the HTTP request handler for /goform/aspRemoteApConfTempSend on the UTT HiPER 840G router. The handler reads the remoteSrcTemp argument from the incoming request and copies it into a fixed-size buffer without validating the input length. Supplying an oversized value overruns the destination buffer and corrupts adjacent memory on the stack or heap.

Because the router exposes this endpoint through its administrative web service, exploitation requires only network reachability to the management interface and low-privilege credentials. The CWE-119 classification reflects improper restriction of operations within the bounds of a memory buffer, a recurring weakness in embedded router firmware written in C.

Root Cause

The root cause is missing length validation on the remoteSrcTemp parameter before it is copied into a stack or heap buffer in the firmware's web administration component. The handler relies on unsafe string-copy semantics and trusts client-supplied input. No canary, ASLR, or other mitigations are documented for the affected firmware, which increases the reliability of memory corruption primitives derived from this flaw.

Attack Vector

An attacker reaches the affected handler over the network by issuing a POST or GET request to the /goform/aspRemoteApConfTempSend endpoint with an oversized remoteSrcTemp value. The attack vector is Network with Low complexity, and the disclosed proof-of-concept describes the exact parameter manipulation required. The vulnerability mechanism is described in the public GitHub CVE Documentation and in the VulDB #316268 Details record. Successful exploitation can disrupt router operation or, depending on memory layout, allow code execution in the context of the firmware's web service.

Detection Methods for CVE-2025-7570

Indicators of Compromise

HTTP requests to /goform/aspRemoteApConfTempSend containing abnormally long remoteSrcTemp parameter values.
Unexpected reboots, watchdog resets, or crashes of the UTT HiPER 840G web management service.
Outbound connections initiated from the router to unknown infrastructure following inbound requests to the affected endpoint.
Configuration changes to remote AP settings that were not made by an authorized administrator.

Detection Strategies

Inspect web access logs on the router or upstream proxies for requests targeting /goform/aspRemoteApConfTempSend and flag entries where remoteSrcTemp exceeds expected length.
Deploy network intrusion detection signatures that match oversized parameter values in HTTP POST bodies destined for the router management interface.
Correlate management-interface access from non-administrative source IP addresses with subsequent router instability events.

Monitoring Recommendations

Forward router syslog and HTTP access logs to a centralized logging or SIEM platform for retention and correlation.
Alert on any external (WAN-side) access attempts to the router's HTTP management interface.
Monitor for repeated crashes or unscheduled restarts of the affected device, which can indicate exploitation attempts.

How to Mitigate CVE-2025-7570

Immediate Actions Required

Restrict access to the router's web management interface to trusted internal management VLANs or specific administrator IP addresses.
Disable WAN-side administrative access on the UTT HiPER 840G immediately if it is currently enabled.
Rotate all administrative credentials on the device to reduce the value of any captured low-privilege accounts.
Inventory deployed UTT HiPER 840G units and prioritize replacement or isolation of devices running firmware 3.1.1-190328 or earlier.

Patch Information

No vendor patch is available at the time of publication. According to the NVD entry, the vendor was contacted about this disclosure but did not respond. Organizations should monitor the VulDB #316268 Citation record and UTT's official channels for any future firmware update. Until a fix is released, compensating controls described in the Workarounds section are the only mitigation.

Workarounds

Place affected routers behind an upstream firewall and block inbound HTTP/HTTPS traffic to the management interface from untrusted networks.
Apply ACLs that restrict the /goform/aspRemoteApConfTempSend endpoint to authenticated administrative sessions originating from a management subnet.
Where feasible, replace the affected UTT HiPER 840G with a supported router that receives active firmware maintenance.
Segment the router from sensitive internal assets so that a compromise of the device does not provide lateral movement paths.

bash

# Example: block external access to the router's web management interface
# Replace ROUTER_IP and MGMT_SUBNET with values for your environment
iptables -A FORWARD -p tcp -d ROUTER_IP --dport 80  -s MGMT_SUBNET -j ACCEPT
iptables -A FORWARD -p tcp -d ROUTER_IP --dport 443 -s MGMT_SUBNET -j ACCEPT
iptables -A FORWARD -p tcp -d ROUTER_IP --dport 80  -j DROP
iptables -A FORWARD -p tcp -d ROUTER_IP --dport 443 -j DROP