CVE-2025-6399: Critical Buffer Overflow Vulnerability in TOTOLINK X15

Overview

A critical vulnerability has been discovered in the TOTOLINK X15 1.0.0-B20230714.1105 router, which, if exploited, could lead to system compromise and potential data leakage. The vulnerability resides in an unknown function of the file /boafrm/formIPv6Addr, which is a part of the HTTP POST Request Handler component. Due to the lack of proper input validation, a malicious actor can manipulate the argument ‘submit-url’ leading to a buffer overflow condition. Given the high severity of this vulnerability, it is crucial for system administrators and users of the affected device to understand the threat and take the necessary mitigation steps.

Vulnerability Summary

CVE ID: CVE-2025-6399
Severity: Critical (CVSS: 8.8)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

TOTOLINK X15 | 1.0.0-B20230714.1105

How the Exploit Works

The vulnerability exists due to inadequate input validation in the HTTP POST Request Handler component’s /boafrm/formIPv6Addr file. When a specially crafted POST request is sent with a manipulated ‘submit-url’ argument, it can cause a buffer overflow condition. This buffer overflow can potentially allow the attacker to execute arbitrary code, leading to full system compromise or data leakage. The exploit can be triggered remotely and does not require any user interaction or privileges.

Conceptual Example Code

Here’s a conceptual example of how the vulnerability might be exploited. This is a sample HTTP POST request:

POST /boafrm/formIPv6Addr HTTP/1.1
Host: vulnerable.totolink.com
Content-Type: application/x-www-form-urlencoded
submit-url=<malicious_payload>

In this request, `` is the manipulated variable that triggers the buffer overflow condition. This payload could consist of a specially crafted string that exceeds the buffer limit, possibly containing malicious code intended to be executed upon successful exploitation.

Mitigation

Users of the affected TOTOLINK X15 router are strongly advised to apply the vendor-provided patch as soon as possible to mitigate this vulnerability. If the patch cannot be applied immediately, users should consider deploying a Web Application Firewall (WAF) or Intrusion Detection System (IDS) as a temporary measure to detect and block attempts to exploit this vulnerability. Always ensure to follow good security practices, such as regularly updating systems and monitoring network traffic for suspicious activities.