CVE-2025-15391 is a command injection vulnerability identified in the D-Link DIR-806A 100CNb11 router model. The flaw resides in the ssdpcgi_main function of the SSDP (Simple Service Discovery Protocol) Request Handler component. SSDP is used for network device discovery, and improper input validation in this function allows an attacker to inject and execute arbitrary system commands remotely. The vulnerability requires no authentication or user interaction, making it accessible to remote attackers scanning for vulnerable devices. The CVSS 4.0 score of 5.3 reflects a medium severity, considering the ease of exploitation (network attack vector, low attack complexity) but limited impact scope due to the product being out of support and the absence of known active exploitation. Since the product is no longer maintained, no official patches or firmware updates are available, increasing the risk of exploitation over time. The public availability of exploit code further raises the threat level. Successful exploitation can lead to full compromise of the router, allowing attackers to manipulate network traffic, intercept sensitive data, or launch further attacks on connected systems. The vulnerability affects only the specific firmware version 100CNb11, limiting the affected population but still significant given the widespread use of D-Link routers in home and small office environments.

For European organizations, particularly small businesses and residential users relying on the D-Link DIR-806A 100CNb11 router, this vulnerability can lead to unauthorized remote control of network infrastructure. Attackers could intercept confidential communications, alter network configurations, or disrupt internet connectivity, impacting confidentiality, integrity, and availability. The lack of vendor support means no patches are forthcoming, increasing the risk of exploitation over time. This is especially concerning for organizations with limited IT resources that may not regularly update or replace networking equipment. The vulnerability could also be leveraged as a foothold for lateral movement within corporate or home networks, potentially exposing sensitive data or enabling further attacks. Given the router’s typical deployment in less monitored environments, detection and response may be delayed, exacerbating potential damage.

Since no official patches or firmware updates are available for the affected D-Link DIR-806A 100CNb11 devices, the primary mitigation is to replace the vulnerable routers with supported models that receive regular security updates. Network segmentation should be implemented to isolate vulnerable devices from critical systems and sensitive data. Disable or restrict SSDP services if possible to reduce the attack surface. Employ network intrusion detection systems (NIDS) to monitor for unusual SSDP traffic or command injection patterns. Regularly audit network devices to identify unsupported or outdated hardware. Educate users about the risks of using unsupported devices and encourage timely hardware upgrades. If replacement is not immediately feasible, consider deploying firewall rules to block incoming SSDP requests from untrusted networks. Maintain up-to-date asset inventories to track vulnerable devices and prioritize remediation efforts.