CVE-2025-57636 is an OS command injection vulnerability identified in the D-Link C1 device, specifically within the jhttpd component's sub_47F028 function. The vulnerability arises from improper sanitization of the HTTP parameter "time", which allows an attacker to inject arbitrary operating system commands. When exploited, this flaw could enable remote attackers to execute arbitrary commands on the underlying operating system with the privileges of the affected service, potentially leading to full system compromise. The vulnerability is present in the D-Link C1 device firmware version dated 2020-02-21, although exact affected versions are not specified. The jhttpd component is likely a lightweight HTTP server embedded in the device for management or configuration purposes. Exploitation requires sending a crafted HTTP request with a malicious "time" parameter to the vulnerable endpoint. There is no indication that authentication is required to exploit this vulnerability, which increases the risk. No public exploits have been reported in the wild yet, and no patches or mitigations have been officially published at the time of this report. The absence of a CVSS score suggests this is a newly disclosed vulnerability. Given the nature of OS command injection, an attacker could leverage this to execute arbitrary commands, potentially leading to data theft, device manipulation, or pivoting into internal networks.

For European organizations using D-Link C1 devices, this vulnerability poses a significant security risk. The ability to execute arbitrary OS commands remotely could lead to unauthorized access to sensitive information, disruption of network services, or use of the compromised device as a foothold for further attacks within the corporate network. This is particularly critical for organizations relying on these devices for network management or security functions. The lack of authentication requirement means that attackers could exploit the vulnerability from the internet or internal networks without credentials. This could result in confidentiality breaches, integrity violations through unauthorized configuration changes, and availability issues if the device is disrupted or taken offline. Additionally, exploitation could facilitate lateral movement to other systems, increasing the overall impact. The threat is heightened in sectors with stringent data protection requirements such as finance, healthcare, and critical infrastructure within Europe, where device compromise could lead to regulatory penalties and operational disruptions.

Organizations should immediately identify any D-Link C1 devices in their environment, especially those running firmware versions around or prior to 2020-02-21. Network segmentation should be applied to isolate these devices from critical infrastructure and sensitive data networks. Access to device management interfaces should be restricted to trusted administrators via VPN or secure management networks. Implement strict firewall rules to block unauthorized inbound HTTP requests to these devices. Monitor network traffic for suspicious HTTP requests containing unusual "time" parameter values. Since no official patches are currently available, consider disabling or restricting the jhttpd service if feasible. Engage with D-Link support channels to obtain information on forthcoming patches or firmware updates. Additionally, apply intrusion detection/prevention systems (IDS/IPS) signatures to detect potential exploitation attempts. Regularly audit device configurations and logs for signs of compromise. Finally, prepare incident response plans specific to IoT and network device breaches to respond promptly if exploitation is detected.