CVE-2025-7506 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 fromNatlimit function located in the /goform/Natlimit endpoint. The vulnerability arises due to improper handling 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, potentially resulting in denial of service. The vulnerability is remotely exploitable without requiring user interaction or authentication, making it particularly dangerous. The CVSS 4.0 base score is 8.7 (high severity), reflecting the ease of exploitation (network attack vector, low complexity), no privileges or user interaction needed, and high impact on confidentiality, integrity, and availability. Although no public exploits have been observed in the wild yet, the exploit code has been disclosed publicly, increasing the risk of imminent attacks. The affected product, Tenda FH451, is a consumer-grade router commonly used in home and small office environments. The vulnerability could allow attackers to take full control of the device, intercept or manipulate network traffic, or disrupt network connectivity.

For European organizations, especially small businesses and home offices relying on Tenda FH451 routers, this vulnerability poses a significant risk. Exploitation could lead to unauthorized access to internal networks, interception of sensitive data, or disruption of internet connectivity. This is particularly concerning for remote workers or distributed teams using these devices as their primary network gateway. Compromise of these routers could also serve as a foothold for lateral movement into corporate networks or be leveraged in larger botnet campaigns targeting European infrastructure. The high severity and remote exploitability increase the urgency for mitigation. Organizations in sectors with sensitive data or critical operations could face confidentiality breaches, operational downtime, and reputational damage if exploited.

Immediate mitigation steps include isolating affected Tenda FH451 devices from critical networks and restricting remote management access. Network administrators should monitor traffic for unusual POST requests targeting the /goform/Natlimit endpoint and implement intrusion detection signatures specific to this exploit. Since no official patch is currently available, consider replacing vulnerable devices with updated models or alternative routers from vendors with active security support. Employ network segmentation to limit the impact of a compromised router and enforce strict firewall rules to block unsolicited inbound traffic to router management interfaces. Additionally, organizations should maintain up-to-date inventories of network devices to quickly identify affected units and apply compensating controls such as VPNs or secure tunnels to protect sensitive communications until patches are released.