CVE-2025-4453 is a command injection vulnerability identified in the D-Link DIR-619L router, specifically affecting firmware version 2.04B04. The vulnerability resides in the function formSysCmd, where improper sanitization or validation of the sysCmd argument allows an attacker to inject arbitrary commands. This flaw can be exploited remotely without requiring user interaction or authentication, making it a significant risk. However, the vulnerability only affects devices running an outdated and unsupported firmware version, limiting the scope of impact to legacy deployments. The CVSS 4.0 base score is 5.3 (medium severity), reflecting the fact that while the attack vector is network-based and requires no user interaction, it does require low privileges (PR:L) and has limited impact on confidentiality, integrity, and availability (VC:L, VI:L, VA:L). No known exploits are currently reported in the wild, and no patches have been released due to the product's end-of-life status. The vendor was notified early, but no remediation is available. The vulnerability could allow attackers to execute arbitrary system commands on the affected router, potentially leading to unauthorized control, network traffic interception, or pivoting within the victim's network.

For European organizations, the impact of this vulnerability depends largely on the presence of legacy D-Link DIR-619L devices running the vulnerable firmware. Such devices, if still operational in enterprise or home office environments, could serve as entry points for attackers to gain unauthorized access to internal networks. Compromise of these routers could lead to interception or manipulation of network traffic, disruption of internet connectivity, or lateral movement to other critical systems. Given the medium severity and limited scope, the impact is moderate but should not be underestimated in environments where these devices are still in use. Organizations relying on outdated network hardware may face increased risk of targeted attacks, especially if these devices are exposed to the internet or poorly segmented from critical infrastructure.

Since the affected product is no longer supported and no patches are available, the primary mitigation is to replace the D-Link DIR-619L routers running firmware 2.04B04 with modern, supported devices that receive regular security updates. In the interim, organizations should isolate these legacy devices from critical network segments and restrict remote management access, ideally disabling WAN-side administration entirely. Network-level protections such as firewall rules should block unauthorized inbound traffic to the router's management interfaces. Monitoring network traffic for unusual command execution patterns or unexpected outbound connections from these devices can help detect exploitation attempts. Additionally, organizations should conduct asset inventories to identify any remaining vulnerable routers and prioritize their replacement or segmentation. Employing network segmentation and zero-trust principles will reduce the risk of lateral movement if a device is compromised.