{"id":"CVE-2026-93633","summary":"Zimbra Collaboration Suite Briefcase CSS Sanitization Bypass via Non-ASCII Stylesheet Characters","details":"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.","modified":"2026-11-08T02:47:43.430300016Z","published":"2026-10-23T13:25:21.365Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93633.json","unresolved_ranges":[{"extracted_events":[{"strategy":"StandardRange","range":[{"last_affected":"10.1.20"}],"source":"AFFECTED_FIELD"}]}],"cna_assigner":"rapid7","cwe_ids":["CWE-79"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93633.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93633"},{"type":"ADVISORY","url":"https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories"},{"type":"ARTICLE","url":"https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/zimbra/zm-build","events":[{"introduced":"0"},{"last_affected":"c4837c66360979d757890271f6c976727e71bcad"}],"database_specific":{"extracted_events":[{"cpe":"cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*","range":[{"introduced":"0"},{"last_affected":"10.1.20"}],"source":"CPE_RANGE"}]}}],"versions":["10.1.20","10.1.16","10.1.14","10.1.13","10.1.10","10.1.6","10.1.5","10.1.4","10.1.1","10.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93633.json"}},{"ranges":[{"type":"GIT","repo":"https://github.com/zimbra/zm-mailbox","events":[{"introduced":"0"},{"last_affected":"c80d2bbf562968d44fa90edd843f1985026585c3"}],"database_specific":{"extracted_events":[{"cpe":"cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*","range":[{"introduced":"0"},{"last_affected":"10.1.20"}],"source":"CPE_RANGE"}]}}],"versions":["10.1.20","10.1.18","10.1.17","10.1.16","10.1.14","10.1.13","10.1.10","10.1.8","10.1.7","10.1.6","10.1.5","10.1.4","10.1.3","10.1.2","10.1.1","10.1.0","8.8.11"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93633.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"}]}