CVE-2025-6165: Totolink X15 Buffer Overflow Vulnerability

CVE-2025-6165 Overview

CVE-2025-6165 is a buffer overflow vulnerability in the TOTOLINK X15 router running firmware version 1.0.0-B20230714.1105. The flaw resides in the HTTP POST Request Handler at the /boafrm/formTmultiAP endpoint. Attackers can trigger the overflow by manipulating the submit-url argument in a crafted POST request. The vulnerability is remotely exploitable over the network and the exploit has been disclosed publicly. This issue is tracked under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer) and affects internet-facing consumer networking equipment.

Critical Impact
Remote attackers can corrupt memory on affected TOTOLINK X15 routers, potentially leading to arbitrary code execution or denial of service against the device.

Affected Products

TOTOLINK X15 hardware device
TOTOLINK X15 Firmware version 1.0.0-B20230714.1105
Devices exposing the /boafrm/formTmultiAP HTTP endpoint

Discovery Timeline

2025-06-17 - CVE-2025-6165 published to NVD
2025-06-23 - Last updated in NVD database

Technical Details for CVE-2025-6165

Vulnerability Analysis

The vulnerability exists in the HTTP POST Request Handler component of the TOTOLINK X15 router firmware. The handler processes requests sent to the URI /boafrm/formTmultiAP, which is part of the router's multi-AP configuration interface. The submit-url parameter supplied in the POST body is copied into a fixed-size buffer without proper length validation. When an attacker submits an oversized value, adjacent memory is overwritten, producing a classic stack or heap buffer overflow condition.

TOTOLINK devices commonly run a customized boa HTTP server, where form handlers are linked into native binaries. Memory corruption in this context can crash the web service, reboot the device, or allow execution of attacker-controlled instructions depending on protections present in the firmware build.

Root Cause

The root cause is missing bounds checking on user-supplied input passed to the submit-url argument. The form handler does not validate or truncate the input length before performing a copy into a finite buffer. This corresponds to [CWE-119], where operations are performed outside the bounds of an allocated memory region.

Attack Vector

Exploitation requires network access to the router's web management interface. An attacker sends a crafted HTTP POST request to /boafrm/formTmultiAP containing an oversized submit-url parameter. Authentication requirements depend on whether the targeted endpoint enforces session validation in the affected firmware build. Once the buffer is overflowed, the attacker can corrupt control-flow data and influence execution within the HTTP service.

The vulnerability mechanism is described in the public GitHub CVE Documentation and the VulDB #312640 Report. No verified exploit code is reproduced here; refer to the linked advisories for technical specifics.

Detection Methods for CVE-2025-6165

Indicators of Compromise

HTTP POST requests targeting /boafrm/formTmultiAP containing abnormally long submit-url values
Unexpected reboots, crashes, or unavailability of the router's web management interface
Outbound connections from the router to unknown hosts following suspicious inbound HTTP activity
Unauthorized changes to wireless or multi-AP configuration on affected devices

Detection Strategies

Inspect network traffic for HTTP POST requests to /boafrm/formTmultiAP with parameter values exceeding expected lengths
Deploy IDS/IPS signatures that flag oversized form parameters destined for TOTOLINK administrative endpoints
Correlate router availability alerts with preceding HTTP requests to identify exploitation attempts

Monitoring Recommendations

Forward router and perimeter firewall logs to a centralized SIEM for analysis of inbound management-plane traffic
Alert on any external source attempting to reach the LAN-side management interface of edge routers
Track firmware versions across managed networking equipment and flag devices running 1.0.0-B20230714.1105

How to Mitigate CVE-2025-6165

Immediate Actions Required

Restrict access to the router's web administration interface to trusted internal hosts only
Disable remote/WAN-side management on the TOTOLINK X15 if currently enabled
Inventory all TOTOLINK X15 devices and identify those running firmware 1.0.0-B20230714.1105
Monitor the Totolink Security Page for an official firmware update addressing CVE-2025-6165

Patch Information

At the time of publication, no vendor advisory or fixed firmware version has been linked in the NVD record for CVE-2025-6165. Administrators should consult the Totolink Security Page for updates and apply patches as soon as they are released.

Workarounds

Place the router behind a network segment that blocks untrusted access to TCP ports serving the web management interface
Replace affected TOTOLINK X15 units with devices receiving active security support if no patch becomes available
Use network ACLs to drop inbound HTTP POST requests to /boafrm/formTmultiAP from untrusted sources

bash

# Example: restrict management interface access using iptables on an upstream firewall
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -s <trusted_mgmt_subnet> -j ACCEPT
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -j DROP