CVE-2022-42999 is a high-severity command injection vulnerability identified in the D-Link DIR-816 A2 router firmware version 1.10 B05. The vulnerability exists in the web interface endpoint /goform/setSysAdm, specifically through the admuser and admpass parameters. These parameters are used to set system administrator credentials, but due to insufficient input validation or sanitization, an attacker can inject arbitrary commands. This vulnerability is classified under CWE-78 (Improper Neutralization of Special Elements used in an OS Command), which allows attackers to execute arbitrary OS commands on the affected device. The CVSS v3.1 base score is 7.5, indicating a high severity, with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. This means the attack can be performed remotely over the network without any authentication or user interaction, and while it does not impact confidentiality or integrity directly, it causes a complete loss of availability (denial of service or device control). No known exploits in the wild have been reported yet, and no official patches or vendor advisories are linked in the provided data. The vulnerability allows an unauthenticated remote attacker to execute arbitrary commands on the router, potentially leading to device compromise, network disruption, or use of the device as a pivot point for further attacks.

For European organizations, this vulnerability poses a significant risk, especially for those relying on the D-Link DIR-816 A2 router model in their network infrastructure. Exploitation could lead to denial of service, rendering critical network gateways inoperable, or allow attackers to gain control over the router to intercept, manipulate, or redirect network traffic. This could compromise internal network security, enable lateral movement, or facilitate further attacks such as data exfiltration or ransomware deployment. Small and medium enterprises (SMEs) and home office setups using this router model are particularly vulnerable due to typically weaker network defenses. The lack of authentication requirement means attackers can exploit this vulnerability remotely without prior access, increasing the attack surface. Given the router’s role as a network edge device, successful exploitation can disrupt business continuity and impact availability of internet services, which is critical for operational resilience in European organizations.

Since no official patch or vendor advisory is currently available, European organizations should take immediate compensating controls. First, restrict remote access to the router’s administrative interface by disabling WAN-side management or limiting access via firewall rules to trusted IP addresses only. Network segmentation should be enforced to isolate vulnerable routers from critical internal systems. Monitoring network traffic for unusual patterns or command injection attempts targeting /goform/setSysAdm can help detect exploitation attempts. Organizations should consider replacing affected devices with updated models or alternative vendors that have released patches. If replacement is not immediately feasible, applying custom firewall rules or intrusion prevention system (IPS) signatures to block malicious payloads targeting admuser and admpass parameters can reduce risk. Regularly auditing router firmware versions and configurations, and educating IT staff about this vulnerability, will improve preparedness. Finally, organizations should stay alert for vendor updates or community patches and apply them promptly once available.