CVE-2025-4355 is a critical heap-based buffer overflow vulnerability identified in the Tenda DAP-1520 wireless access point, specifically affecting version 1.10B04_BETA02. The vulnerability resides in the set_ws_action function within the /dws/api/ endpoint. An attacker can remotely exploit this flaw without requiring user interaction or prior authentication, as indicated by the CVSS vector (AV:N/AC:L/AT:N/UI:N/PR:L). The vulnerability allows an attacker to manipulate input data to overflow a heap buffer, potentially leading to arbitrary code execution, denial of service, or system compromise. The CVSS 4.0 base score of 8.7 reflects a high severity, with 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 vulnerability does not require network segmentation bypass or user interaction, making it highly exploitable in exposed network environments. The affected device, Tenda DAP-1520, is a widely used consumer and small business wireless access point, often deployed in home and office networks. The lack of an official patch or mitigation from the vendor at the time of publication further elevates the risk for affected users.

For European organizations, this vulnerability poses a significant risk, especially for small and medium enterprises (SMEs) and home office environments that rely on Tenda DAP-1520 devices for network connectivity. Successful exploitation could lead to unauthorized access to internal networks, data exfiltration, or disruption of network services. Given the device's role as a network access point, compromise could serve as a foothold for lateral movement within corporate networks, potentially impacting sensitive data and critical infrastructure. The vulnerability's remote exploitability without authentication increases the attack surface, particularly for organizations with exposed management interfaces or insufficient network segmentation. Additionally, the public availability of exploit code may accelerate targeted attacks against European entities, especially those with limited cybersecurity resources. The potential for service disruption could affect business continuity, while data breaches could lead to regulatory penalties under GDPR, amplifying the overall impact.

1. Immediate network-level controls: Restrict access to the management interface of Tenda DAP-1520 devices by implementing firewall rules that limit access to trusted IP addresses only. 2. Network segmentation: Isolate vulnerable devices on separate VLANs or network segments to reduce the risk of lateral movement in case of compromise. 3. Monitor network traffic for anomalous activity targeting /dws/api/ endpoints, especially unusual POST requests to set_ws_action functions. 4. Disable remote management features if not required, or restrict them to secure VPN access only. 5. Regularly audit and inventory network devices to identify all instances of Tenda DAP-1520 and verify firmware versions. 6. Engage with Tenda support channels to obtain or request official patches or firmware updates addressing this vulnerability. 7. Implement intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics capable of detecting exploitation attempts targeting this vulnerability. 8. Educate IT staff on the risks and signs of exploitation to enable rapid incident response. 9. Consider replacing vulnerable devices with models from vendors with robust security update policies if patches are unavailable or delayed.