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

Summary

CVE-2025-66376 is a advisory from CISA-KEV. Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting Vulnerability Vendor: Synacor. Severity/Threat: high. This item is marked as actively exploited. Source updated on 2026-03-18.

Product

Zimbra Collaboration Suite (ZCS)

What to do

General, cautious steps (verify details in the official source):

• Prioritize patching or mitigation immediately (treat as actively risky).
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Check logs/telemetry for indicators of compromise and suspicious activity.
• Consider temporary hardening: restrict access, reduce attack surface, and monitor aggressively.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

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