CVE-2026-1506 identifies a critical OS command injection vulnerability in the D-Link DIR-615 router firmware version 4.10. The flaw resides in the MAC Filter Configuration feature, specifically within the /adv_mac_filter.php script, where the 'mac' parameter is improperly sanitized. This allows an attacker to inject arbitrary operating system commands remotely without requiring authentication or user interaction. The vulnerability is exploitable over the network, enabling attackers to execute commands with the privileges of the web server process, potentially leading to full device compromise. The vulnerability has a CVSS 4.0 base score of 8.6, indicating high severity, with network attack vector, low attack complexity, no privileges required, and no user interaction needed. The affected product is no longer supported by D-Link, and no official patches are available, increasing the risk of exploitation as proof-of-concept code has been publicly disclosed. This vulnerability can be leveraged to disrupt network operations, intercept or manipulate traffic, or pivot into internal networks, posing significant risks to organizations still operating these legacy devices.

For European organizations, the impact of CVE-2026-1506 can be severe. Compromise of the D-Link DIR-615 routers could lead to unauthorized access to internal networks, data interception, and manipulation, as well as disruption of network availability. Given the router's role as a gateway device, attackers could establish persistent footholds, launch further attacks against internal systems, or exfiltrate sensitive information. The lack of vendor support means organizations cannot rely on official patches, increasing exposure duration. Sectors with legacy infrastructure, including small and medium enterprises, educational institutions, and some public sector entities, may be particularly vulnerable. The vulnerability could also affect home office environments, indirectly impacting corporate networks through VPNs or remote access. The overall risk is heightened by the public availability of exploit code, which lowers the barrier for attackers.

Since no official patches are available for the affected D-Link DIR-615 firmware version 4.10, organizations should prioritize replacing the vulnerable hardware with supported models that receive regular security updates. In cases where immediate replacement is not feasible, network segmentation should be implemented to isolate the affected devices from critical infrastructure and sensitive data. Access to the router's management interface must be restricted using firewall rules to allow only trusted IP addresses. Monitoring network traffic for unusual patterns or command injection attempts targeting the MAC filter functionality can help detect exploitation attempts. Additionally, disabling the MAC filter feature if not required can reduce the attack surface. Organizations should also educate users about the risks of using unsupported hardware and enforce policies to phase out legacy devices. Regular network vulnerability assessments should include checks for outdated routers and their firmware versions.