Overview
CVE-2025-6137 is a critical vulnerability found in TOTOLINK T10 version 4.1.8cu.5207. This vulnerability affects the function setWiFiScheduleCfg of the file /cgi-bin/cstecgi.cgi of the component HTTP POST Request Handler. It allows an attacker to trigger a buffer overflow through the manipulation of the ‘desc’ argument. Since the vulnerability is exploitable remotely and has been made public, it poses a significant threat to any system running the affected software. This vulnerability matters because it could potentially lead to a system compromise or data leakage.
Vulnerability Summary
CVE ID: CVE-2025-6137
Severity: Critical (CVSS: 8.8)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leak
Affected Products
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Product | Affected Versions
TOTOLINK T10 | 4.1.8cu.5207
How the Exploit Works
The vulnerability lies in the setWiFiScheduleCfg function of the /cgi-bin/cstecgi.cgi file. This function fails to properly sanitize the ‘desc’ argument in HTTP POST requests, leading to a buffer overflow. An attacker can exploit this by sending a specially crafted HTTP POST request that contains an excessively long ‘desc’ argument. This causes the system to overflow its buffer, allowing the attacker to execute arbitrary code or disrupt the system’s normal operations.
Conceptual Example Code
Here’s a conceptual example of how the vulnerability might be exploited:
POST /cgi-bin/cstecgi.cgi HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
desc=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA... (continue until buffer overflow is triggered)In this example, the ‘desc’ argument in the POST request is filled with an excessively long string, which results in a buffer overflow on the target system.
Recommended Mitigation
It’s recommended to apply the vendor-supplied patch as soon as possible to mitigate this vulnerability. In the meantime, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can offer temporary protection against potential exploits. These systems can be configured to block or alert on HTTP POST requests to /cgi-bin/cstecgi.cgi that contain unusually long ‘desc’ arguments.