CVE-2017-16933: etc/initsystem/prepare-dirs in Icinga 2.x through 2.8.1 has a chown call for a filename in a user-writable directory, which allows local users to gain privileges by leveraging access to the $ICINGA2_USER account for creation of a link.
CVE-2018-6532: An issue was discovered in Icinga 2.x through 2.8.1. By sending specially crafted (authenticated and unauthenticated) requests, an attacker can exhaust a lot of memory on the server side, triggering the OOM killer.
CVE-2018-6533: An issue was discovered in Icinga 2.x through 2.8.1. By editing the init.conf file, Icinga 2 can be run as root. Following this the program can be used to run arbitrary code as root. This was fixed by no longer using init.conf to determine account information for any root-executed code (a larger issue than CVE-2017-16933).
CVE-2018-6534: An issue was discovered in Icinga 2.x through 2.8.1. By sending specially crafted messages, an attacker can cause a NULL pointer dereference, which can cause the product to crash.
CVE-2018-6535: An issue was discovered in Icinga 2.x through 2.8.1. The lack of a constant-time password comparison function can disclose the password to an attacker.
CVE-2018-6536: An issue was discovered in Icinga 2.x through 2.8.1. The daemon creates an icinga2.pid file after dropping privileges to a non-root account, which might allow local users to kill arbitrary processes by leveraging access to this non-root account for icinga2.pid modification before a root script executes a "kill `cat /pathname/icinga2.pid`" command, as demonstrated by icinga2.init.d.cmake.
CVE-2020-29663: Icinga 2 v2.8.0 through v2.11.7 and v2.12.2 has an issue where revoked certificates due for renewal will automatically be renewed, ignoring the CRL. This issue is fixed in Icinga 2 v2.11.8 and v2.12.3.