{"identifier":"CVE-2025-66376","cve":{"id":"CVE-2025-66376","description":"Zimbra Collaboration (ZCS) 10 before 10.0.18 and 10.1 before 10.1.13 allows Classic UI stored XSS via Cascading Style Sheets (CSS) @import directives in an HTML e-mail message.","published":"2026-01-05T15:15:44.903000+00:00","modified":"2026-10-07T10:10:00.213000+00:00","status":"Analyzed","score":7.2,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N","cvss_version":"3.1","affected":[{"criteria":"cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*","versionStartIncluding":"10.0.0","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"10.0.18"},{"criteria":"cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*","versionStartIncluding":"10.1.0","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"10.1.13"}],"weaknesses":["CWE-79"],"references":[{"url":"https://wiki.zimbra.com/wiki/Security_Center","source":"cve@mitre.org","tags":["Release Notes","Vendor Advisory"]},{"url":"https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.18#Security_Fixes","source":"cve@mitre.org","tags":["Release Notes"]},{"url":"https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.13#Security_Fixes","source":"cve@mitre.org","tags":["Release Notes"]},{"url":"https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy","source":"cve@mitre.org","tags":["Product"]},{"url":"https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories","source":"cve@mitre.org","tags":["Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-66376","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","tags":["US Government Resource"]}],"kev":{"cveID":"CVE-2025-66376","vendorProject":"Synacor","product":"Zimbra Collaboration Suite (ZCS)","vulnerabilityName":"Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting Vulnerability","dateAdded":"2026-03-18","shortDescription":"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.","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.","dueDate":"2026-04-01","knownRansomwareCampaignUse":"Unknown","forensicTriage":"No","notes":"https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories ; 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