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 resides in the HTTP POST request handler component, within the function frmL7ProtForm located in the /goform/L7Prot endpoint. The vulnerability arises due to improper handling and validation of the 'page' argument, which can be manipulated by an attacker to overflow the stack buffer. This overflow can lead to arbitrary code execution or cause the device to crash, resulting in denial of service. The vulnerability is remotely exploitable without requiring user interaction or prior authentication, increasing its risk profile. The CVSS 4.0 score of 8.7 (high severity) reflects the ease of exploitation (network attack vector, low attack complexity), no privileges or user interaction required, and the potential for high impact on confidentiality, integrity, and availability. Although no known exploits are currently observed in the wild, the public disclosure of the exploit code increases the likelihood of active exploitation attempts. This vulnerability affects a widely deployed consumer and small office/home office (SOHO) router model, which is often used to provide internet connectivity and network segmentation. Successful exploitation could allow attackers to gain control over the device, intercept or manipulate network traffic, pivot to internal networks, or disrupt service availability.

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. Compromise of these routers could lead to unauthorized access to internal networks, interception of sensitive communications, and potential lateral movement to other critical systems. This could result in data breaches, intellectual property theft, or disruption of business operations. Additionally, the availability of the device could be impacted, causing network outages. Given the remote exploitability and lack of authentication requirements, attackers could launch widespread automated attacks targeting vulnerable devices across Europe. The risk is heightened in sectors with less mature cybersecurity practices or limited IT resources to promptly patch or replace vulnerable devices.

To mitigate this vulnerability, European organizations should first verify if they are using Tenda FH451 routers running firmware version 1.0.0.9. Immediate steps include: 1) Applying any available firmware updates or patches from Tenda as soon as they are released; 2) If no patch is available, consider replacing the affected devices with models from vendors with a stronger security track record; 3) Restrict remote management access to the router by disabling WAN-side administration or limiting access via firewall rules; 4) Monitor network traffic for unusual activity that could indicate exploitation attempts; 5) Employ network segmentation to isolate vulnerable devices from critical infrastructure; 6) Educate users about the risks and encourage regular device updates; 7) Use intrusion detection/prevention systems (IDS/IPS) tuned to detect exploitation attempts targeting this vulnerability. These targeted actions go beyond generic advice by focusing on device-specific controls and network architecture adjustments to reduce exposure.