CVE-2026-73973: Linuxfabrik Monitoring-Plugins

Medium severity, CVSS 5.5. EPSS: 0.3% chance of exploitation in the next 30 days.

Linuxfabrik Monitoring Plugins provides monitoring plugins for Icinga, Nagios, and related systems. Prior to version 7.0.0, check-plugins/logfile/logfile accepted a free-form --filename path and opened it as root when invoked through the shipped nagios or icinga sudoers allowlist, without confining the resolved path to /var/log. An attacker who controls the monitoring account can select a root-readable file such as /etc/shadow and use --warning-regex . while leaving SUPPRESS_OUTPUT false, causing each nonempty line to be collected in warn_matches and returned through lib.base.oao(). The vulnerable flow passes the expanded scan_path directly to open(), and neither real-path containment nor an allowlist protects the sink. The same fix also confines mysql-logfile and openvpn-client-list paths, allows only documented log roots, and resolves symlinks and parent-directory traversal before checking containment. This issue is fixed in version 7.0.0.

Affected products

• Linuxfabrik Monitoring-Plugins: before 7.0.0 (fixed in 7.0.0)

Published 2026-08-18. Last modified 2026-09-09.