CVE-2024-11253 is an OS command injection vulnerability classified under CWE-78 affecting the Zyxel VMG8825-T50K router firmware versions V5.50(ABOM.8.5)C0 and earlier. The flaw exists in the handling of the "DNSServer" parameter within the device's diagnostic function. An attacker who has already obtained administrator-level authentication can inject malicious operating system commands via this parameter due to improper neutralization of special elements. This vulnerability allows execution of arbitrary commands on the underlying operating system, potentially leading to full device compromise. The vulnerability has a CVSS v3.1 base score of 7.2, reflecting high severity with network attack vector, low attack complexity, and no user interaction required. The impact includes full confidentiality, integrity, and availability compromise of the affected device. Although no public exploits are currently reported, the vulnerability poses a significant risk given the administrative access requirement and the critical role of the device in network infrastructure. No official patches have been published yet, so mitigation relies on access control and monitoring. The vulnerability highlights the importance of secure input validation in embedded device firmware, especially for diagnostic and administrative functions.

The impact of CVE-2024-11253 is substantial for organizations using Zyxel VMG8825-T50K routers. Successful exploitation allows an attacker with admin credentials to execute arbitrary OS commands, potentially leading to full device takeover. This can result in unauthorized access to network traffic, disruption of network services, and pivoting to other internal systems. Confidentiality is at risk as attackers may intercept or manipulate sensitive data. Integrity can be compromised by altering device configurations or injecting malicious code. Availability may be affected if the attacker disrupts router functionality or launches denial-of-service conditions. Given the device’s role as a network gateway, the vulnerability could facilitate broader network compromise. Organizations relying on these routers for critical infrastructure or business operations face increased risk of operational disruption, data breaches, and persistent attacker presence. The lack of a current patch increases exposure duration, emphasizing the need for immediate mitigation.

1. Restrict administrative access to the Zyxel VMG8825-T50K routers by limiting management interfaces to trusted networks and IP addresses only. 2. Enforce strong authentication mechanisms and regularly rotate administrator credentials to reduce risk of credential compromise. 3. Monitor router logs and network traffic for unusual commands or diagnostic function usage that could indicate exploitation attempts. 4. Disable or restrict access to diagnostic functions if not required for operational purposes. 5. Implement network segmentation to isolate vulnerable devices from critical systems and sensitive data. 6. Regularly check Zyxel’s official channels for firmware updates addressing this vulnerability and apply patches promptly once available. 7. Employ intrusion detection/prevention systems (IDS/IPS) to detect anomalous command injection patterns targeting the device. 8. Conduct periodic security assessments and penetration tests focusing on router configurations and firmware vulnerabilities. These steps go beyond generic advice by focusing on access control, monitoring, and operational restrictions specific to this vulnerability’s attack vector and affected functionality.