CVE-2025-29522 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 router's ping function, which allows an unauthenticated remote attacker to inject arbitrary commands. This is classified under CWE-77 (Improper Neutralization of Special Elements used in a Command), indicating that the input to the ping function is not properly sanitized before being passed to a system shell. The vulnerability has a CVSS 3.1 base score of 6.5, reflecting a medium severity level. The vector string (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N) indicates that the attack can be performed remotely over the network without any privileges or user interaction, and it impacts confidentiality and integrity but not availability. Although no known exploits are currently reported in the wild, the nature of command injection vulnerabilities typically allows attackers to execute arbitrary commands on the device, potentially leading to unauthorized access to sensitive information or manipulation of device configurations. The lack of a patch or mitigation link suggests that no official fix has been released yet, increasing the urgency for affected users to implement alternative protective measures. The affected firmware version dates back to late 2021, which may imply that many deployed devices could still be running this vulnerable version if not updated or replaced.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on the D-Link DSL-7740C routers in their network infrastructure. Exploitation could lead to unauthorized disclosure of sensitive network information (confidentiality impact) and unauthorized modification of router settings or data (integrity impact). Since the vulnerability does not affect availability directly, denial-of-service is less of a concern. However, compromised routers could be used as footholds for lateral movement within corporate networks or as part of botnets for broader attacks. Given that the attack requires no authentication or user interaction and can be executed remotely, the risk of exploitation is elevated in environments where these routers are exposed to untrusted networks or the internet. For organizations in Europe, this could mean exposure of internal network configurations, interception of traffic, or disruption of secure communications if attackers manipulate routing or firewall rules. Additionally, the lack of a patch increases the window of exposure, necessitating immediate risk mitigation to protect sensitive data and maintain network integrity.

Since no official patch is currently available, European organizations should take proactive steps to mitigate the risk. First, isolate the vulnerable routers from direct internet exposure by placing them behind firewalls or VPNs, restricting access to trusted management networks only. Disable or restrict the use of the ping function or any remote management features that invoke it, if possible. Monitor network traffic for unusual command execution patterns or unexpected outbound connections originating from these devices. Implement network segmentation to limit the impact of a compromised router on critical systems. Regularly audit firmware versions and plan for firmware upgrades or device replacements with models that have confirmed security updates. Employ intrusion detection/prevention systems (IDS/IPS) tuned to detect command injection attempts targeting network devices. Finally, maintain an incident response plan specific to network device compromise scenarios to quickly contain and remediate any detected exploitation.