Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability

Date Apr 20, 2026
Type KEV
Signal Known exploited
Vendor / Product Synacor ยท Zimbra Collaboration Suite (ZCS)
CVE CVE-2025-48700
Known exploited CVE-2025-48700

Summary

Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting vulnerability that could allow attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information.

Why it matters

CVE-2025-48700 is listed in CISA's Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. CISA remediation deadline: 2026-04-23. Treat remediation as urgent.

Operator check

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Sources

PatchBrief uses public sources. It does not scan environments, verify exposure, or replace vendor guidance.