{"id":"CVE-2026-93633","aliases":[],"title":"Zimbra Collaboration Suite Briefcase CSS Sanitization Bypass via Non-ASCII Stylesheet Characters","titleSource":"rapid7","descriptionSource":"rapid7","products":[{"vendor":"Zimbra","name":"Zimbra Collaboration Suite","platforms":[],"versions":[{"version":"0","status":"affected","lessThanOrEqual":"10.1.20","versionType":"semver"}],"defaultStatus":"unaffected","source":"rapid7","url":"https://www.cve.org/CVERecord?id=CVE-2026-93633"}],"remediation":[],"description":"A CSS sanitization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user with Briefcase access to publish a document that displays attacker-controlled content under the Zimbra origin. When processing a stylesheet containing non-ASCII characters, DefangFilter appends the final ASCII segment without sanitizing it. HTML stored as application/x-zimbra-doc can therefore retain CSS URL references that the normal sanitizer removes. An attacker can share a crafted document that loads external resources and displays a credential-collection form using Zimbra's own visual assets. Exploitation requires the victim to open the document in a browser that renders the content type inline; credential theft additionally requires form submission. ZCS 10.1.16 and 10.1.20 are affected.","severity":"medium","score":5.4,"published":"2026-10-23T13:25:21.365Z","modified":"2026-10-28T19:51:07.972Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories","https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/"],"sources":[{"name":"CVE","id":"CVE-2026-93633","modified":"2026-10-28T19:51:07.972Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-93633"}],"assessments":[{"source":"rapid7","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","score":5.4}],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-29T04:15:31.644Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}