{"id":"CVE-2025-66376","url":"https://www.cyber-defence.io/tools/cve/CVE-2025-66376","generatedAt":"2026-10-31T05:59:58.487Z","title":"Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting Vulnerability","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":"2026-01-05T15:15:45.000Z","lastModified":"2026-10-07T10:10:00.000Z","status":"Analyzed","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":6.1,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},"cwe":["CWE-79"],"affected":["synacor/zimbra collaboration suite"],"epss":{"score":0.20227,"percentile":0.97463,"date":"2026-10-30","history":[{"date":"2026-10-07","score":0.17294,"percentile":0.97037},{"date":"2026-10-08","score":0.20227,"percentile":0.97411}]},"kev":{"listed":true,"dateAdded":"2026-03-18","dueDate":"2026-04-01","knownRansomwareCampaignUse":"Unknown","notes":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.\nhttps://wiki.zimbra.com/wiki/Zimbra_Security_Advisories ; https://nvd.nist.gov/vuln/detail/CVE-2025-66376"},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 1 April 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[],"references":[{"url":"https://wiki.zimbra.com/wiki/Security_Center","tags":["Release Notes","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.18#Security_Fixes","tags":["Release Notes"],"source":"cve@mitre.org"},{"url":"https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.13#Security_Fixes","tags":["Release Notes"],"source":"cve@mitre.org"},{"url":"https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy","tags":["Product"],"source":"cve@mitre.org"},{"url":"https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-66376","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-66376","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}