Nagios Log Server versions prior to 2026R1.0.1 are vulnerable to local privilege escalation due to a combination of sudo misconfiguration and group-writable application directories. The 'www-data' user is a member of the 'nagios' group, which has write access to '/usr/local/nagioslogserver/scripts', while several scripts in this directory are owned by root and may be executed via sudo without a password. A local attacker running as 'www-data' can move one of these root-owned scripts to a backup name and create a replacement script with attacker-controlled content at the original path, then invoke it with sudo.

This allows arbitrary commands to be executed with root privileges, providing full compromise of the underlying operating system.