CVE-2026-2042 is an OS command injection vulnerability classified under CWE-78, found in the monitoringwizard module of Nagios Host version 2026R1. The flaw arises from insufficient sanitization of user-supplied input before it is passed to system calls, enabling an authenticated attacker to inject arbitrary OS commands. This vulnerability allows remote code execution (RCE) in the context of the Nagios service account, potentially compromising the host system's confidentiality, integrity, and availability. The attack vector is network-based, requiring authentication but no further user interaction. The CVSS v3.0 base score is 7.2, reflecting high severity with network attack vector, low attack complexity, high privileges required, and no user interaction. While no public exploits have been observed, the vulnerability poses a significant risk due to the critical role Nagios plays in IT infrastructure monitoring. The lack of proper input validation in a core monitoring module makes this a serious concern for organizations relying on Nagios Host for system health and availability monitoring.

Successful exploitation of this vulnerability can lead to full remote code execution under the Nagios service account, potentially allowing attackers to manipulate monitoring data, disrupt monitoring services, or pivot to other systems within the network. This compromises the confidentiality of monitored data, the integrity of monitoring results, and the availability of the monitoring infrastructure itself. Given Nagios Host's widespread use in enterprise and critical infrastructure environments, this could result in undetected system failures, delayed incident response, and broader network compromise. The requirement for authentication limits exposure somewhat, but insider threats or compromised credentials could be leveraged to exploit this flaw. The impact extends to operational disruption and potential data breaches, making it a high-risk vulnerability for organizations worldwide.

Organizations should immediately review access controls to restrict authentication to trusted users only, minimizing the risk of credential compromise. Applying vendor patches or updates as soon as they become available is critical. In the absence of patches, administrators should consider disabling or restricting access to the monitoringwizard module or any functionality that processes user-supplied input for system calls. Implement strict input validation and sanitization on all user inputs within Nagios Host configurations. Network segmentation and monitoring for unusual Nagios Host activity can help detect exploitation attempts. Employ multi-factor authentication (MFA) to reduce the risk of unauthorized access. Regularly audit Nagios Host logs for suspicious commands or anomalies. Finally, maintain up-to-date backups and incident response plans to quickly recover from potential compromises.