CVE-2025-29516 is a command injection vulnerability identified in the D-Link DSL-7740C router, specifically in the firmware version DSL7740C.V6.TR069.20211230. The vulnerability arises from improper input validation in the device's backup function, which allows an attacker to inject arbitrary commands. Command injection vulnerabilities enable an attacker to execute arbitrary system-level commands on the affected device, potentially leading to full control over the router. Since the backup function is typically used to export or save configuration data, it may be accessible via the device's web interface or remote management protocols, increasing the attack surface. Exploitation could allow an attacker to manipulate router settings, intercept or redirect network traffic, deploy malware, or pivot into internal networks. Although no known exploits are currently reported in the wild, the presence of this vulnerability in a widely deployed network device firmware version poses a significant risk. The lack of a CVSS score indicates that the vulnerability is newly disclosed and not yet fully assessed. The absence of patch information suggests that no official fix has been released at the time of this report, emphasizing the need for immediate mitigation efforts by affected users and organizations.

For European organizations, the impact of this vulnerability could be substantial. The D-Link DSL-7740C is a broadband router often used by ISPs and enterprises for internet connectivity. Successful exploitation could compromise the confidentiality and integrity of sensitive data traversing the network, disrupt availability by causing device malfunctions or reboots, and enable attackers to establish persistent footholds within corporate or ISP networks. This could lead to data breaches, interception of communications, or lateral movement to other critical infrastructure. Given the strategic importance of telecommunications infrastructure in Europe and the reliance on such devices for both residential and business internet access, exploitation could affect service continuity and trust in network providers. Additionally, compromised routers could be leveraged in larger botnet campaigns or as launch points for attacks against other targets within Europe.

To mitigate this vulnerability, European organizations and users of the D-Link DSL-7740C should: 1) Immediately restrict access to the router’s management interfaces, especially the backup function, by limiting it to trusted internal networks and disabling remote management if not required. 2) Monitor network traffic for unusual activity indicative of command injection attempts or unauthorized configuration changes. 3) Employ network segmentation to isolate critical systems from devices running vulnerable firmware. 4) Contact D-Link or service providers to inquire about firmware updates or patches addressing this vulnerability and apply them promptly once available. 5) As a temporary measure, consider disabling the backup function if feasible or replacing affected devices with models confirmed to be secure. 6) Implement strong authentication and change default credentials to reduce the risk of unauthorized access. 7) Maintain up-to-date intrusion detection/prevention systems tuned to detect exploitation attempts targeting this vulnerability.