{"id":"CVE-2026-93633","title":"Zimbra Collaboration Suite Briefcase CSS Sanitization Bypass via Non-ASCII Stylesheet Characters","summary":"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…","severity":"medium","cvss":5.4,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","cvssSource":"cna","cwe":["CWE-79"],"vendor":"Zimbra","product":"Zimbra Collaboration Suite","affected":["collaboration_suite <= 10.1.20"],"published":"2026-10-23","updated":"2026-10-23","sourceUpdated":"2026-10-23T13:25:21.365Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-93633","references":[{"url":"https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories"},{"url":"https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/"}],"tags":["cve.org"],"ingestedAt":"2026-10-23T14:28:08.711Z","slug":"CVE-2026-93633","body":"## Overview\n\nA 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.\n\n## Affected\n\n- `collaboration_suite <= 10.1.20`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":29.7,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}