The vulnerability identified as CVE-2025-52079 affects the D-Link DIR-820L router running firmware version 1.06B02. It is caused by improper access control in the administrator password setting functionality. Specifically, an attacker can send a crafted POST request to the /get_set.ccp endpoint to change the administrator password without any authentication or verification. This flaw allows unauthorized users to gain administrative control over the router, potentially enabling them to alter configurations, intercept or redirect network traffic, and deploy further attacks within the network. The vulnerability was reserved in June 2025 and published in October 2025, but no CVSS score or patches have been provided yet, and no exploits are known to be active in the wild. The lack of authentication requirement and the critical role of the administrator password in securing the device make this a serious security issue. The vulnerability primarily impacts the confidentiality, integrity, and availability of the affected routers and the networks they serve. Since the DIR-820L is commonly used in home and small office environments, exploitation could lead to widespread network compromise if attackers gain control. The absence of a patch necessitates alternative mitigations such as network access restrictions and monitoring for suspicious POST requests targeting the vulnerable endpoint.

For European organizations, this vulnerability could result in unauthorized administrative access to network routers, leading to full compromise of the device. Attackers could change router settings, disable security features, redirect traffic to malicious servers, or create persistent backdoors. This would jeopardize the confidentiality and integrity of internal communications and could disrupt availability by causing network outages or degraded performance. Small and medium enterprises that rely on the DIR-820L for internet connectivity and network management are particularly at risk. The exploitation could facilitate lateral movement within corporate networks or enable interception of sensitive data. Additionally, compromised routers could be leveraged as part of botnets or for launching further attacks. The lack of authentication and ease of exploitation increase the likelihood of successful attacks, especially in environments where the router management interface is exposed or poorly segmented from user networks.

Since no official patch is currently available, organizations should implement the following mitigations: 1) Restrict access to the router’s management interface by limiting it to trusted internal IP addresses and disabling remote management over WAN. 2) Employ network segmentation to isolate router management traffic from general user traffic. 3) Monitor network traffic for unusual POST requests to the /get_set.ccp endpoint and alert on suspicious activity. 4) Change default credentials and use strong passwords to reduce the risk of unauthorized access if the vulnerability is exploited. 5) Consider replacing affected devices with models from vendors that provide timely security updates. 6) Regularly check for firmware updates from D-Link and apply patches as soon as they become available. 7) Use intrusion detection/prevention systems (IDS/IPS) to detect and block exploitation attempts targeting this vulnerability. 8) Educate IT staff about this vulnerability and ensure incident response plans include steps for compromised network devices.