Nagios Log Server versions prior to 2026R1.0.1 contain an authenticated command injection vulnerability in the experimental 'Natural Language Queries' feature. When this feature is configured, certain user-controlled settings—including model selection and connection parameters—are read from the global configuration and concatenated into a shell command that is executed via shell_exec() without proper input handling or command-line argument sanitation. An authenticated user with access to the 'Global Settings' page can supply crafted values in these fields to inject additional shell commands, resulting in arbitrary command execution as the 'www-data' user and compromise of the Log Server host.