Nagios 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.
Use CWE-732, Nagios vendor hub and Nagios Xi product page to widen CVE-2025-34287 into its surrounding weakness, vendor, and product context.
Compare it with CVE-2024-13997, CVE-2025-34286 and CVE-2026-2043 for nearby disclosures in the same product family.