CVE-2022-37042: Synacor Zimbra Collaboration Suite (ZCS) Authentication Bypass Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2022-08-11. EPSS: 91.9% chance of exploitation in the next 30 days.

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.

Affected products

• Synacor Zimbra Collaboration Suite: version 8.8.15 only; version 9.0.0 only

Published 2022-08-12. Last modified 2026-08-04.