CVE-2018-20160

Severity: critical (CVSS 9.8 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2019-05-29 · updated 2026-06-17
Weakness: CWE-611

Description

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

Zimbra Collaboration: from 8.7.0 before 8.7.11; from 8.8.0 before 8.8.9; 8.7.11, 8.7.11-p1, 8.7.11-p2, 8.7.11-p3, 8.7.11-p4, 8.7.11-p5 (+17) — fixed in 8.7.11, 8.8.9

How to fix

Upgrade to a fixed version: Zimbra Collaboration 8.7.11, 8.8.9. Check the vendor advisory for mitigations.

References

https://bugzilla.zimbra.com/show_bug.cgi?id=109093
https://wiki.zimbra.com/wiki/Security_Center
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
https://bugzilla.zimbra.com/show_bug.cgi?id=109093
https://wiki.zimbra.com/wiki/Security_Center
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories

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