PNP4Nagios through 0.6.26 has /usr/bin/npcd and npcd.cfg owned by an unprivileged account but root code execution depends on these files, which allows local users to gain privileges by leveraging access to this unprivileged account.
Gentoo Linux Security Advisory 201806-9 - A vulnerability in PNP4Nagios which may allow local attackers to gain root privileges. Versions less than 0.6.26-r9 are affected.