CVE-2025-7530 is a critical stack-based buffer overflow vulnerability identified in the Tenda FH1202 router, specifically affecting firmware version 1.2.0.14(408). The flaw exists in the fromPptpUserAdd function within the /goform/PPTPDClient component, which processes the Username argument. An attacker can remotely exploit this vulnerability by sending a specially crafted Username parameter, causing a stack-based buffer overflow. This overflow can lead to arbitrary code execution or denial of service, as it allows overwriting of the stack memory. The vulnerability requires no user interaction and can be triggered remotely over the network, increasing its risk profile. The CVSS 4.0 base score is 8.7 (high severity), reflecting the ease of remote exploitation without authentication and the potential for high impact on confidentiality, integrity, and availability. Although no known exploits are currently reported in the wild, public disclosure of the exploit code increases the likelihood of active exploitation. The vulnerability affects a widely deployed consumer and small office/home office (SOHO) router model, which is often used to provide network connectivity and VPN services via PPTP. Given the critical nature of the flaw and the common use of the affected device, this vulnerability represents a significant security risk if left unpatched.

For European organizations, the impact of CVE-2025-7530 can be substantial. Many small and medium enterprises (SMEs) and home offices rely on Tenda FH1202 routers for internet connectivity and VPN access. Exploitation could allow attackers to gain unauthorized access to internal networks, intercept or manipulate sensitive data, or disrupt network availability. This could lead to data breaches, intellectual property theft, or operational downtime. Additionally, compromised routers could be used as footholds for lateral movement within corporate networks or as part of botnets for broader attacks. The vulnerability's remote exploitability without authentication makes it particularly dangerous in environments where these routers are exposed to untrusted networks or the internet. European organizations with remote workers or branch offices using this device are at increased risk, especially if they have not updated firmware or implemented compensating controls. The potential for disruption and data compromise could also have regulatory implications under GDPR, increasing legal and financial risks.

1. Immediate firmware update: Organizations should verify the firmware version of their Tenda FH1202 routers and upgrade to a patched version once released by the vendor. If no patch is currently available, contact Tenda support for guidance. 2. Network segmentation: Isolate vulnerable routers from critical internal networks and restrict management interfaces to trusted IP addresses only. 3. Disable PPTP VPN services if not required, as this is the attack vector for the vulnerability. 4. Implement firewall rules to block unauthorized access to router management and VPN ports from external networks. 5. Monitor network traffic for unusual activity or signs of exploitation attempts targeting the /goform/PPTPDClient endpoint. 6. Consider replacing affected devices with more secure alternatives if timely patching is not feasible. 7. Educate IT staff about this vulnerability and ensure incident response plans include steps for dealing with potential exploitation. These measures go beyond generic advice by focusing on the specific vulnerable function and attack vector, emphasizing immediate firmware management, network controls, and monitoring tailored to the Tenda FH1202 environment.