CVE-2025-7527 is a critical stack-based buffer overflow vulnerability identified in the Tenda FH1202 router, specifically version 1.2.0.14(408). The flaw exists in the function fromAdvSetWan within the /goform/AdvSetWan endpoint. The vulnerability arises due to improper handling of the PPPOEPassword 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, making it highly dangerous. The CVSS 4.0 score of 8.7 (high severity) reflects the ease of exploitation (network attack vector, low attack complexity, no privileges required) and the significant 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 risk of imminent attacks. The vulnerability affects a widely deployed consumer and small business router model, which is often used to provide internet connectivity in home and office environments. Successful exploitation could allow attackers to gain control over the router, intercept or manipulate network traffic, or disrupt network availability.

For European organizations, this vulnerability poses a substantial risk, especially for small and medium enterprises (SMEs) and home office setups relying on Tenda FH1202 routers. Compromise of these devices can lead to unauthorized network access, data interception, and lateral movement within internal networks. Confidentiality of sensitive communications may be breached, and integrity of network traffic can be undermined. Availability may also be impacted if the device crashes or is taken offline by attackers. Given the router's role as a network gateway, exploitation could facilitate further attacks on connected systems or enable attackers to establish persistent footholds. The risk is heightened in sectors with sensitive data or critical infrastructure components connected behind these routers. Additionally, the lack of authentication requirement and remote exploitability means attackers can target vulnerable devices en masse, potentially leading to large-scale disruptions or espionage campaigns within European networks.

Immediate mitigation should focus on isolating affected Tenda FH1202 devices from untrusted networks until a patch or firmware update is available. Network administrators should implement strict firewall rules to restrict access to the /goform/AdvSetWan endpoint, ideally blocking external WAN access to router management interfaces. Deploy network segmentation to limit the impact of a compromised router on internal systems. Monitoring network traffic for unusual patterns or signs of exploitation attempts targeting the PPPOEPassword parameter is recommended. Organizations should contact Tenda for official firmware updates addressing this vulnerability and apply them promptly once released. If updates are unavailable, consider replacing affected devices with models from vendors with active security support. Additionally, educating users about the risks and encouraging the use of strong, unique passwords for router management can reduce attack surface. Employing intrusion detection/prevention systems (IDS/IPS) with signatures for this vulnerability may help detect exploitation attempts.