Overview
The Common Vulnerabilities and Exposures (CVE) system has identified a critical stack-based buffer overflow vulnerability, designated as CVE-2025-7530, in Tenda FH1202 version 1.2.0.14(408). This vulnerability exposes systems to potential compromise and data leakage, posing a significant risk to users. The flaw resides in the fromPptpUserAdd function of the /goform/PPTPDClient file, and the manipulation of the Username argument can trigger it. Given the severity of the impact and the fact that the exploit has been publicized, immediate action is required from users and administrators of affected systems.
Vulnerability Summary
CVE ID: CVE-2025-7530
Severity: Critical (8.8 CVSS Severity Score)
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
Tenda FH1202 | 1.2.0.14(408)
How the Exploit Works
The vulnerability resides in the fromPptpUserAdd function of the /goform/PPTPDClient file within the Tenda FH1202 firmware. A remote attacker can exploit this vulnerability by sending specially crafted data that manipulates the Username argument within this function. As the Username argument is not properly validated, this input results in a stack-based buffer overflow condition. This overflow can allow the attacker to execute arbitrary code, leading to full system compromise or data leakage.
Conceptual Example Code
Below is a conceptual example of how the vulnerability might be exploited. This is a pseudo HTTP POST request to the vulnerable endpoint, carrying a malicious payload that manipulates the Username argument to trigger the buffer overflow:
POST /goform/PPTPDClient?fromPptpUserAdd HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
username=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA...&password=guest123In this example, ‘A’ is repeated multiple times to overflow the username buffer. This is a simplified example and actual exploitation would require crafting a payload that leads to arbitrary code execution.
Mitigation Guidance
Users and administrators are strongly encouraged to apply the vendor-provided patch to mitigate this vulnerability immediately. If a patch cannot be applied immediately, implementing a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) can provide temporary mitigation. These solutions can help detect and block exploitation attempts. It’s also recommended to restrict access to the vulnerable system until the patch is applied to reduce the risk of exploitation.