CVE-2026-2157 is an OS command injection vulnerability identified in the D-Link DIR-823X router firmware version 250416. The vulnerability resides in the function sub_4175CC within the /goform/set_static_route_table endpoint. This function processes parameters such as interface, destip, netmask, gateway, and metric to configure static routing. Improper input validation allows an attacker to inject arbitrary OS commands by manipulating these parameters. The vulnerability is remotely exploitable without requiring user interaction or authentication, making it highly accessible to attackers scanning for vulnerable devices exposed on the internet. Successful exploitation can lead to full compromise of the router, enabling attackers to execute arbitrary commands with high privileges. This can result in network traffic interception, redirection, device control, or pivoting attacks within the internal network. The CVSS v4.0 score of 8.6 reflects the high impact on confidentiality, integrity, and availability, combined with the ease of exploitation. Although no public exploit code is currently confirmed in the wild, the public disclosure increases the risk of imminent exploitation. The lack of an official patch at the time of disclosure necessitates immediate defensive measures to mitigate risk.

For European organizations, exploitation of this vulnerability could lead to severe consequences including unauthorized access to internal networks, interception or manipulation of sensitive data, disruption of network services, and potential lateral movement by attackers to other critical systems. Organizations relying on D-Link DIR-823X routers in their infrastructure, especially in sectors such as government, finance, healthcare, and critical infrastructure, face elevated risks. Compromise of these routers could undermine network perimeter defenses, facilitate espionage, data theft, or sabotage. The vulnerability's remote exploitability without authentication means attackers can target exposed devices directly, increasing the attack surface. This could lead to significant operational disruptions and reputational damage, as well as regulatory compliance issues under GDPR if personal data is compromised. The impact is magnified in environments where these routers serve as primary gateways or are part of segmented networks without additional security controls.

1. Immediately restrict access to the router’s management interfaces by implementing IP whitelisting and disabling remote management where not necessary. 2. Employ network segmentation to isolate vulnerable devices from critical assets and sensitive data flows. 3. Monitor network traffic for unusual patterns or commands indicative of exploitation attempts targeting /goform/set_static_route_table. 4. Apply any available firmware updates from D-Link as soon as they are released to address this vulnerability. 5. If patches are not yet available, consider temporary device replacement or disabling affected features related to static route configuration. 6. Use intrusion detection/prevention systems (IDS/IPS) to detect and block attempts to exploit this vulnerability. 7. Conduct regular vulnerability scans to identify exposed DIR-823X devices and remediate accordingly. 8. Educate network administrators on the risks and signs of exploitation to enable rapid response. 9. Implement strong network access controls and multi-factor authentication for device management where possible. 10. Maintain an incident response plan tailored to router compromise scenarios.