News Summary:
On March 19, 2026, the U.S. Cybersecurity and Infrastructure Security Agency (CISA) added a critical vulnerability affecting the Zimbra Collaboration Suite (ZCS) to its Known Exploited Vulnerabilities (KEV) catalog, confirming active in-the-wild abuse and setting an April 1, 2026, remediation deadline for federal agencies. This followed CISA's urgent order on March 18, 2026, for federal agencies to patch a high-severity cross-site scripting (XSS) vulnerability, identified as CVE-2025-66376, in Zimbra Collaboration Suite, also with an April 1 deadline, after confirming its active exploitation. Previously, on December 22, 2025, the Federal Office for Information Security (BSI) published a security warning for Synacor Zimbra, detailing multiple vulnerabilities that could enable attacks on Linux and UNIX operating systems. Earlier, in October 2025, CISA issued urgent alerts and critical warnings regarding an actively exploited zero-day cross-site scripting (XSS) vulnerability (CVE-2025-27915) in Synacor’s Zimbra Collaboration Suite, specifically impacting the ZCS Classic Web Client and posing significant risks to organizations.
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