CVE-2025-67073 is a critical buffer overflow vulnerability identified in the Tenda AC10V4.0 router firmware version 16.03.10.20, specifically within the httpd binary's fromAdvSetMacMtuWan function. This function processes POST requests sent to the /goform/AdvSetMacMtuWan endpoint, and the vulnerability arises from improper handling of the 'serviceName' field in the request payload. An attacker can craft a malicious POST request with an oversized or specially crafted 'serviceName' value, causing a buffer overflow that can crash the httpd service, resulting in denial of service (DoS). More severely, the overflow may allow an attacker to execute arbitrary code remotely, potentially gaining control over the device. The exploit requires no authentication or user interaction, increasing its risk profile. The vulnerability is classified under CWE-120 (Classic Buffer Overflow), and the CVSS v3.1 base score is 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), reflecting its critical severity and ease of exploitation over the network. Although no patches or official fixes have been released yet, the vulnerability's presence in a widely deployed consumer router model raises concerns about widespread exposure. No known exploits have been reported in the wild as of the publication date, but the potential for rapid weaponization is high given the vulnerability's characteristics.

For European organizations, this vulnerability poses a significant threat to network infrastructure security. Exploitation could lead to complete compromise of affected routers, enabling attackers to intercept, manipulate, or disrupt network traffic. This jeopardizes confidentiality, integrity, and availability of organizational communications and data. Denial of service attacks could disrupt business operations, while remote code execution could allow attackers to pivot into internal networks, deploy malware, or establish persistent backdoors. Organizations relying on Tenda AC10V4.0 routers, especially in small to medium enterprises or home office environments where such consumer-grade devices are common, are at heightened risk. The lack of authentication requirement means attackers can exploit the vulnerability remotely without prior access, increasing the attack surface. This could also impact managed service providers and ISPs using these devices for customer premises equipment. The absence of patches necessitates immediate risk mitigation to prevent exploitation and potential data breaches or service outages.

1. Immediately isolate affected Tenda AC10V4.0 routers from untrusted networks, especially the internet, to prevent remote exploitation. 2. Restrict access to router management interfaces by implementing firewall rules that limit access to trusted IP addresses only. 3. Monitor network traffic for unusual POST requests targeting /goform/AdvSetMacMtuWan, particularly those containing suspicious 'serviceName' payloads. 4. Where possible, replace vulnerable devices with models from vendors with timely security update practices. 5. Employ network segmentation to limit the impact of potential router compromise, ensuring critical systems are on separate VLANs or subnets. 6. Use intrusion detection/prevention systems (IDS/IPS) to detect and block exploitation attempts targeting this vulnerability. 7. Stay informed on vendor advisories for patches or firmware updates addressing this issue and apply them promptly once available. 8. Educate IT staff about this vulnerability and the importance of securing network devices, including consumer-grade routers. 9. Consider deploying network access control (NAC) solutions to enforce device compliance and prevent vulnerable devices from connecting to sensitive networks.