Overview
The Common Vulnerabilities and Exposures (CVE) system has recently detailed a critical vulnerability with the identifier CVE-2025-8138, found in TOTOLINK A702R version 4.0.0-B20230721.1521. This vulnerability, if exploited, can lead to serious security breaches, system compromise, and potential data leakage. It is of critical importance to any individual or organization using the affected TOTOLINK product to understand and mitigate this vulnerability as soon as possible.
Vulnerability Summary
CVE ID: CVE-2025-8138
Severity: Critical (CVSS: 8.8)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
TOTOLINK A702R | 4.0.0-B20230721.1521
How the Exploit Works
The vulnerability resides in an unknown functionality of the file /boafrm/formOneKeyAccessButton in the HTTP POST Request Handler component of the TOTOLINK A702R firmware. The exploitation of this vulnerability involves the manipulation of the ‘submit-url’ argument, which can cause a buffer overflow. This buffer overflow may then result in undefined behavior, potentially leading to system compromise and data leakage.
Conceptual Example Code
An attacker might exploit this vulnerability by sending a maliciously crafted HTTP POST request similar to the following:
POST /boafrm/formOneKeyAccessButton HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
submit-url=www.example.com%00[insert malicious payload here]In this example, the ‘submit-url’ argument is appended with a null byte (%00) followed by a malicious payload. This causes an overflow in the buffer that stores the ‘submit-url’ data, which can lead to unintended consequences, potentially compromising the system and leaking data.
Mitigation Guidance
It is highly recommended to apply a vendor-supplied patch as soon as possible. If a patch is not immediately available or feasible, consider using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to temporarily mitigate the vulnerability by monitoring network traffic and blocking or alerting on suspicious activity.