{"cvss":7.2,"datePublished":"2026-03-18","dateUpdated":"2026-03-18","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.","dueDate":"2026-04-01","id":"CVE-2025-66376","kev_catalogs":["cisa"],"knownRansomwareCampaignUse":"Unknown","notes":"https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories ; https://nvd.nist.gov/vuln/detail/CVE-2025-66376","product":"Zimbra Collaboration Suite (ZCS)","requiredAction":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.","severity":"HIGH","source":"cisa_known_exploited","title":"Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting Vulnerability","vendor":"Synacor"}