{"id":"CVE-2026-93628","revision":"f3028f2299ed4a53909eac27b7206972","records":[{"revision":"f3028f2299ed4a53909eac27b7206972","observedAt":"2026-10-23T16:01:20.601+00:00","statement":{"source":"cve-program","id":"CVE-2026-93628","aliases":[],"title":"Zimbra Collaboration Suite Calendar Processing Authentication Bypass via Forged iCalendar REPLY Attendee Response","description":"An attendee authentication vulnerability in the email calendar processing of Zimbra Collaboration Suite (ZCS) allows an unauthenticated sender to forge another attendee's response to an existing meeting. Zimbra passes a null sender identity when processing iCalendar REPLY components, causing the attendee authorization filter to be skipped. An attacker who knows the meeting UID, organizer address and attendee address can send a non-outdated reply that changes the attendee's participation status in the organizer's calendar. The change occurs automatically during delivery without organizer or attendee interaction. ZCS 10.1.16 and 10.1.21 are affected.","state":0,"publishedAt":"2026-10-23T13:18:16.368+00:00","modifiedAt":"2026-10-23T13:18:16.368+00:00","affected":[{"ecosystem":"Vendor product","name":"Zimbra Collaboration Suite","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Zimbra\",\n                    \"product\": \"Zimbra Collaboration Suite\",\n                    \"versions\": [\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"0\",\n                            \"lessThanOrEqual\": \"10.1.21\",\n                            \"versionType\": \"semver\"\n                        }\n                    ],\n                    \"defaultStatus\": \"unaffected\"\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3,"severity":"MEDIUM"}],"references":["https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories","https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-93628","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-93628","identifiers":["CVE-2026-93628"]},"retained":false,"historicalAffected":[]}],"coverage":[]}