CVE-2018-20160: Synacor Zimbra Collaboration Suite

Critical severity, CVSS 9.8. EPSS: 2.2% chance of exploitation in the next 30 days.

ZxChat (aka ZeXtras Chat), as used for zimbra-chat and zimbra-talk in Synacor Zimbra Collaboration Suite 8.7 and 8.8 and in other products, allows XXE attacks, as demonstrated by a crafted XML request to mailboxd.

Affected products

• Synacor Zimbra Collaboration Suite: from 8.7.0, before 8.7.11 (fixed in 8.7.11); from 8.8.0, before 8.8.9 (fixed in 8.8.9); version 8.7.11 only; version 8.8.9 only; version 8.8.10 only; version 8.8.11 only

Published 2019-05-29. Last modified 2026-06-17.