CVE-2025-66376 1

CVE-2025-66376: Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting Vulnerability

Known Exploited Vulnerabilities CISA KEV Catalog Mar 18, 2026

Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting vulnerability in the Classic UI where attackers could abuse Cascading Style Sheets (CSS) @import directives in email HTML.

Vulnerabilities & Patching