DescriptionNagios XI versions prior to 2024R2 contain an improperly owned script, process_perfdata.pl, which is executed periodically as the nagios user but owned by www-data. Because the file was writable by www-data, an attacker with web server privileges could modify its contents, leading to arbitrary code execution as the nagios user when the script is next run. This improper ownership and permission configuration enables local privilege escalation.