Nagios Core application version 4.2.4 is vulnerable to Site-Wide Cross-Site Request Forgery (CSRF) in many functions, like adding – deleting for hosts or servers.

Nagios Core 4.4.2 has XSS via the alert summary reports of plugin results, as demonstrated by a SCRIPT element delivered by a modified check_load plugin to NRPE.

qh_core in Nagios Core 4.4.1 and earlier is prone to a NULL pointer dereference vulnerability, which allows attackers to cause a local denial-of-service condition by sending a crafted payload to the listening UNIX socket.

qh_echo in Nagios Core 4.4.1 and earlier is prone to a NULL pointer dereference vulnerability, which allows attackers to cause a local denial-of-service condition by sending a crafted payload to the listening UNIX socket.

Nagios Core through 4.3.4 initially executes /usr/sbin/nagios as root but supports configuration options in which this file is owned by a non-root account (and similarly can have nagios.cfg owned by a non-root account), which allows local users to gain privileges by leveraging access to this non-root account.