All CVE records
CVE-2025-66376 — Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting Vulnerability
CISA KEV listed
Added March 18, 2026 Remediate by April 1, 2026
Description
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.
Notes
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories ; https://nvd.nist.gov/vuln/detail/CVE-2025-66376
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