Applied Cybernetics Group
Threat intel → detection pipeline
Friday, September 18, 2026
Data as of 13:09 UTC

known ransomware use

Synacor Zimbra Collaboration Suite (ZCS) Authentication Bypass Vulnerability

Added to KEV
2022-08-11
Federal due date
2022-09-01
Vendor
Synacor
Product
Zimbra Collaboration Suite (ZCS)
EPSS
99.8th percentile (score 0.919, as of 2026-09-16)
NVD CVSS v3.1
9.8 (CRITICAL)
Ransomware use
Known
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2022-37042

CISA short description

Synacor Zimbra Collaboration Suite (ZCS) contains an authentication bypass vulnerability in MailboxImportServlet. This vulnerability was chained with CVE-2022-27925 which allows for unauthenticated remote code execution.

Required action

Apply updates per vendor instructions.

NVD description

Zimbra Collaboration Suite (ZCS) 8.8.15 and 9.0 has mboximport functionality that receives a ZIP archive and extracts files from it. By bypassing authentication (i.e., not having an authtoken), an attacker can upload arbitrary files to the system, leading to directory traversal and remote code execution. NOTE: this issue exists because of an incomplete fix for CVE-2022-27925.

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.