CVE-2021-27927

Name	CVE-2021-27927
Description	In Zabbix from 4.0.x before 4.0.28rc1, 5.0.0alpha1 before 5.0.10rc1, 5.2.x before 5.2.6rc1, and 5.4.0alpha1 before 5.4.0beta2, the CControllerAuthenticationUpdate controller lacks a CSRF protection mechanism. The code inside this controller calls diableSIDValidation inside the init() method. An attacker doesn't have to know Zabbix user login credentials, but has to know the correct Zabbix URL and contact information of an existing user with sufficient privileges.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severity	medium

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
zabbix (PTS)	stretch	1:3.0.7+dfsg-3	fixed
	stretch (security)	1:3.0.32+dfsg-0+deb9u1	fixed
	buster	1:4.0.4+dfsg-1	vulnerable
	bullseye, sid	1:5.0.8+dfsg-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
zabbix	source	stretch	(not affected)
zabbix	source	(unstable)	1:5.0.8+dfsg-1

Notes

[buster] - zabbix <no-dsa> (Minor issue)
[stretch] - zabbix <not-affected> (Vulnerable code introduced later)
https://support.zabbix.com/browse/ZBX-18942
CControllerAuthenticationUpdate introduced by authentication revamp in https://support.zabbix.com/browse/ZBXNEXT-4573 (4.0)