CVE-2025-66376: Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting Vulnerability
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. Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
· high severity · unattributed attribution
Evidence and provenance
- Original source
- CISA KEV report ↗
- Published
- 2026-03-18T00:00:00Z
- Confidence basis
- No actor match
- Record ID
fd4a8e139c7f392599e6
Vulnerabilities
CVE-2025-66376
Use and citation
Verify the original report before making operational decisions. Cite this permanent page together with the original source, publication date, confidence level, and review status.