CVE-2025-29517 is a command injection vulnerability identified in the D-Link DSL-7740C router, specifically in the firmware version DSL7740C.V6.TR069.20211230. The vulnerability resides in the traceroute6 function, which is used to perform IPv6 traceroute operations. Command injection vulnerabilities occur when an attacker can inject arbitrary commands into a system shell or command interpreter due to insufficient input validation or improper sanitization of user-supplied data. In this case, the traceroute6 function likely accepts input parameters that are not properly sanitized, allowing an attacker to execute arbitrary system commands on the affected device. Exploiting this vulnerability could allow an attacker to gain unauthorized control over the router, potentially leading to full compromise of the device. This could enable attackers to intercept or manipulate network traffic, pivot into internal networks, disrupt network availability, or deploy further malware. The vulnerability was published on August 25, 2025, and no CVSS score has been assigned yet. There are no known exploits in the wild at the time of publication, and no patches or mitigations have been officially released. The lack of a CVSS score and patch information suggests that this vulnerability is newly disclosed and may require urgent attention from affected organizations. Given that the affected device is a widely deployed DSL router model, this vulnerability poses a significant risk to network infrastructure relying on this hardware, especially in environments where IPv6 traceroute functionality is enabled or exposed to untrusted users.

For European organizations, the impact of CVE-2025-29517 could be substantial. Many enterprises, ISPs, and small-to-medium businesses across Europe utilize D-Link DSL routers for internet connectivity. A successful command injection attack on these routers could compromise the confidentiality, integrity, and availability of network communications. Attackers could intercept sensitive data, redirect traffic, or launch further attacks within corporate networks. The exploitation of this vulnerability could also lead to denial of service conditions, disrupting business operations. Given the increasing adoption of IPv6 in Europe, the traceroute6 function is likely to be actively used, increasing the attack surface. Additionally, critical infrastructure sectors such as finance, healthcare, and government agencies that rely on secure and stable network connectivity could be targeted, amplifying the potential consequences. The absence of known exploits currently provides a window for proactive mitigation, but the risk remains high due to the ease of exploitation typical of command injection flaws and the potential for remote exploitation without authentication if the vulnerable function is exposed externally.

Organizations should immediately identify and inventory all D-Link DSL-7740C routers running the affected firmware version. Network administrators should restrict access to the router management interfaces and disable IPv6 traceroute functionality if it is not required. Implement network segmentation to isolate vulnerable devices from critical infrastructure and sensitive data. Employ strict firewall rules to block unauthorized inbound and outbound traffic to and from these routers. Monitor network traffic for unusual traceroute6 requests or other suspicious activity indicative of exploitation attempts. Since no official patches are currently available, organizations should engage with D-Link support for firmware updates or advisories. Where possible, consider replacing affected devices with models that have updated firmware or are not vulnerable. Additionally, applying intrusion detection/prevention systems (IDS/IPS) signatures that detect command injection patterns targeting traceroute6 could provide temporary protection. Finally, maintain regular backups of router configurations and network device states to facilitate rapid recovery if compromise occurs.