Pressing Enter in a text field of a configuration form is known to result in various problems.
For instance, if you open the configuration form of a host with linked templates, then press Enter in any text field and update the form, template linkage is removed (items from the template remain).
IPMI checks will not work with the standard OpenIPMI library from Debian/Ubuntu package. To fix, recompile OpenIPMI library with OpenSSL enabled as discussed in ZBX-6139.
Some Linux distributions like Debian, Ubuntu do not support encrypted private keys (with passphrase) if the libssh2 library is installed from packages. Please see ZBX-4850 for more details.
Zabbix server or proxy that uses MySQL as its database may or may not work correctly with MySQL ODBC library due to an upstream bug. Please see ZBX-7665 for more information and available workarounds.
Web scenarios using the https protocol and Zabbix agent checks
net.tcp.service.perf[https...] may fail if the target server is configured to disallow TLS v1.0 protocol or below. Please see ZBX-9879 for more information and available workarounds.
If the OpenBSD operating system is used, a use-after-free bug in the Net-SNMP library up to the 5.7.3 version can cause a crash of Zabbix server if the SourceIP parameter is set in the Zabbix server configuration file. As a workaround, please do not set the SourceIP parameter. The same problem applies also for Linux, but it does not cause Zabbix server to stop working.
There is a bug in fping versions earlier than v3.10 that mishandles duplicate echo replay packets. This may cause unexpected results for
icmppingsec items. It is recommended to use the latest version of fping. Please see ZBX-11726 for more details.
Zabbix server leaks memory on CentOS 6, CentOS 7 and possibly other related Linux distributions due to an upstream bug when "SSL verify peer" is enabled in web scenarios. Please see ZBX-10486 for more information and available workarounds.
Zabbix server generates slow select queries in case of non-existing values for items. This is caused by a known issue in MySQL 5.6/5.7 versions. A workaround to this is disabling the index_condition_pushdown optimizer in MySQL. For an extended discussion, see ZBX-10652.