CVE-2025-7505 is a critical stack-based buffer overflow vulnerability identified in the Tenda FH451 router, specifically version 1.0.0.9. The flaw exists in the HTTP POST request handler component, within the function frmL7ProtForm located in the /goform/L7Prot endpoint. The vulnerability arises from improper handling of the 'page' argument during HTTP POST requests, which allows an attacker to overflow the stack buffer. This type of vulnerability can lead to arbitrary code execution, potentially allowing remote attackers to execute malicious payloads on the affected device without any authentication or user interaction. The vulnerability is remotely exploitable over the network, increasing its risk profile. Although no public exploits have been observed in the wild yet, the exploit code has been disclosed publicly, making it accessible to threat actors. The CVSS 4.0 base score is 8.7 (high severity), reflecting the ease of exploitation (network vector, no authentication required), and the significant impact on confidentiality, integrity, and availability due to the potential for full system compromise. The vulnerability affects only the specified firmware version 1.0.0.9 of the Tenda FH451 router, which is a consumer and small office/home office (SOHO) networking device. The lack of available patches at the time of disclosure increases the urgency for mitigation and risk management.

For European organizations, the impact of this vulnerability can be significant, especially for small and medium enterprises (SMEs) and home office users relying on Tenda FH451 routers for network connectivity. Successful exploitation could lead to complete compromise of the router, enabling attackers to intercept, manipulate, or redirect network traffic, deploy malware, or establish persistent backdoors within the network perimeter. This can result in data breaches, disruption of business operations, and potential lateral movement into internal networks. Given the router’s role as a gateway device, the compromise could undermine network security controls and expose sensitive information. Critical infrastructure sectors and organizations handling personal data under GDPR may face regulatory and reputational consequences if exploited. The remote and unauthenticated nature of the vulnerability increases the likelihood of exploitation attempts, particularly in environments where these devices are exposed to the internet without adequate firewall protections.

1. Immediate mitigation should include isolating affected Tenda FH451 devices from direct internet exposure by placing them behind additional network security layers such as firewalls or VPNs. 2. Network administrators should monitor network traffic for unusual activity targeting the /goform/L7Prot endpoint or anomalous POST requests. 3. Disable or restrict remote management interfaces on the router to limit exposure. 4. If possible, replace affected devices with alternative routers from vendors with active security support. 5. Regularly check for firmware updates or security advisories from Tenda and apply patches promptly once available. 6. Implement network segmentation to limit the impact of a compromised device. 7. Employ intrusion detection/prevention systems (IDS/IPS) tuned to detect exploitation attempts of this vulnerability. 8. Educate users about the risks of using outdated or unsupported network devices and encourage timely updates or replacements.