Synacor Zimbra Collaboration Suite (ZCS) Improper Restriction of XML External Entity Reference

Added to KEV
2022-01-10
Federal due date
2022-07-10
Vendor
Synacor
Product
Zimbra Collaboration Suite (ZCS)
EPSS
100.0th percentile (score 0.944, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Unknown
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2019-9670

CISA short description

Synacor Zimbra Collaboration Suite (ZCS) contains an improper restriction of XML external entity (XXE) vulnerability in the mailboxd component.

Required action

Apply updates per vendor instructions.

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.