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.
Recommended 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.
CISA remediation due date for U.S. federal agencies: 1 Apr 2026.
Collected automatically from public sources. Verify affected versions and fixes in the vendor's notice before acting.