Icinga 2 is a monitoring system which checks the availability of network resources, notifies users of outages, and generates performance data for reporting. Prior to versions 2.12.12, 2.13.12, and 2.14.6, the VerifyCertificate() function can be tricked into incorrectly treating certificates as valid. This allows an attacker to send a malicious certificate request that is then treated as a renewal of an already existing certificate, resulting in the attacker obtaining a valid certificate that can be used to impersonate trusted nodes. This only occurs when Icinga 2 is built with OpenSSL older than version 1.1.0. This issue has been patched in versions 2.12.12, 2.13.12, and 2.14.6.
Icinga Core through 1.14.0 initially executes bin/icinga as root but supports configuration options in which this file is owned by a non-root account (and similarly can have etc/icinga.cfg owned by a non-root account), which allows local users to gain privileges by leveraging access to this non-root account, a related issue to CVE-2017-14312. This also affects bin/icingastats, bin/ido2db, and bin/log2ido.
Cross-site scripting (XSS) vulnerability in the Classic-UI with the CSV export link and pagination feature in Icinga before 1.14 allows remote attackers to inject arbitrary web script or HTML via the query string to cgi-bin/status.cgi.