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.
Severity
CVSS 3.0
9.8 critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
2.2% chance of exploitation in the next 30 days; higher than 82% of CVEs (scores of 2026-10-31)