CVE-2025-4356 is a critical stack-based buffer overflow vulnerability identified in the Tenda DAP-1520 wireless access point, specifically affecting version 1.10B04_BETA02. The flaw resides in the mod_graph_auth_uri_handler function within the Authentication Handler component, located in the /storage directory of the device's firmware. This vulnerability allows an attacker to remotely trigger a stack-based buffer overflow by sending specially crafted authentication requests to the device. Because the vulnerability is exploitable remotely without requiring user interaction or prior authentication, it presents a significant risk. The buffer overflow can lead to arbitrary code execution, potentially allowing an attacker to take full control of the affected device, disrupt network availability, or pivot to other internal network resources. The CVSS 4.0 base score is 8.7, reflecting high severity due to the network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. Although no public exploits are currently known to be actively used in the wild, the public disclosure of the exploit code increases the risk of imminent exploitation. The vulnerability affects a specific firmware version, indicating that other versions may not be vulnerable or have mitigations in place. However, the presence of a beta firmware version suggests that some deployments might be running this or similar versions in production environments, especially in smaller or less managed networks.

For European organizations, the impact of this vulnerability can be substantial, particularly for enterprises, educational institutions, and public sector entities relying on Tenda DAP-1520 access points for wireless connectivity. Successful exploitation could lead to unauthorized access to internal networks, data exfiltration, disruption of wireless services, and potential lateral movement within corporate networks. This could compromise sensitive personal data protected under GDPR, leading to regulatory penalties and reputational damage. Additionally, the disruption of wireless infrastructure could impact business continuity and operational efficiency. Given the remote exploitability and lack of required authentication, attackers could target these devices en masse, potentially leading to widespread network outages or use of compromised devices as footholds for further attacks. The vulnerability also poses risks to critical infrastructure sectors that utilize such devices for network access, increasing the potential for broader societal impact.

Organizations should immediately identify any Tenda DAP-1520 devices running firmware version 1.10B04_BETA02. Since no official patch links are currently available, organizations should contact Tenda support for firmware updates or advisories. In the interim, network administrators should implement strict network segmentation to isolate vulnerable devices from critical systems and sensitive data. Deploying firewall rules to restrict access to the management interfaces of these devices from untrusted networks can reduce exposure. Monitoring network traffic for anomalous authentication requests targeting the mod_graph_auth_uri_handler function or unusual device behavior is recommended. If possible, replace affected devices with models that have confirmed patched firmware versions. Additionally, organizations should review their asset inventories to ensure no unauthorized or beta firmware devices are in use. Implementing intrusion detection systems with signatures for this vulnerability, once available, will aid in early detection of exploitation attempts.