CVE-2025-7529 is a critical security vulnerability identified in the Tenda FH1202 router, specifically in firmware version 1.2.0.14(408). The flaw exists in the 'fromNatlimit' function within the /goform/Natlimit endpoint. This vulnerability is a stack-based buffer overflow triggered by improper handling of the 'page' argument. An attacker can remotely send a specially crafted request to this endpoint, causing the buffer overflow condition. Due to the nature of stack-based buffer overflows, this can lead to arbitrary code execution, potentially allowing an attacker to take full control of the affected device without requiring any authentication or user interaction. The vulnerability has a CVSS 4.0 base score of 8.7, indicating a high severity level. The vector metrics show that the attack can be performed remotely (AV:N), with low attack complexity (AC:L), no privileges required (PR:L), and no user interaction (UI:N). The impact on confidentiality, integrity, and availability is high (VC:H, VI:H, VA:H), meaning an attacker can fully compromise the device’s data, functionality, and network operations. Although no public exploits are currently known to be actively used in the wild, the exploit code has been disclosed publicly, increasing the risk of exploitation. The Tenda FH1202 is a consumer-grade router commonly used in small offices and homes, but it can also be found in small business environments. Given the router’s role as a network gateway, compromise could allow attackers to intercept, manipulate, or disrupt network traffic, pivot to internal networks, or launch further attacks. The absence of an official patch link suggests that remediation may not yet be available, increasing urgency for mitigation.

For European organizations, the impact of this vulnerability could be significant, especially for small and medium-sized enterprises (SMEs) and home office setups that rely on Tenda FH1202 routers. A successful exploit could lead to full device compromise, allowing attackers to intercept sensitive communications, exfiltrate confidential data, or disrupt network availability. This could result in breaches of GDPR regulations due to unauthorized data access or loss of service. Additionally, compromised routers can be used as footholds for lateral movement within corporate networks or as part of botnets for broader attacks, amplifying the threat landscape. The high severity and remote exploitability make this vulnerability a critical risk for organizations lacking robust network segmentation or monitoring. The lack of authentication requirement means attackers can exploit the vulnerability from outside the network, increasing exposure. The potential for integrity and availability impacts also threatens operational continuity, which is critical for many European businesses.

1. Immediate network segmentation: Isolate Tenda FH1202 devices from critical internal networks to limit potential lateral movement if compromised. 2. Disable remote management interfaces on the affected routers to prevent external exploitation. 3. Monitor network traffic for unusual activity originating from or targeting the router, including unexpected outbound connections or command-and-control traffic. 4. Apply any available firmware updates from Tenda as soon as they are released; if no official patch exists, consider contacting the vendor for guidance or replacing affected devices. 5. Implement strict firewall rules to restrict access to the /goform/Natlimit endpoint or the router’s management interfaces. 6. Use network intrusion detection/prevention systems (IDS/IPS) with signatures for this vulnerability or generic buffer overflow detection to identify exploitation attempts. 7. Educate IT staff and users about the risks and signs of router compromise. 8. As a longer-term measure, evaluate the use of more secure and regularly updated network equipment to reduce exposure to such vulnerabilities.