An organizer authentication vulnerability in the email calendar processing of Zimbra Collaboration Suite (ZCS) allows an unauthenticated sender to cancel or modify an existing meeting in a recipient's calendar. Zimbra accepts iCalendar CANCEL and REQUEST components without verifying that the email sender is authorized to act as the supplied organizer. An attacker who knows the meeting UID and organizer address can supply a non-outdated sequence number to move the recipient's meeting to Trash or replace its details. Processing occurs automatically during email delivery without recipient interaction. ZCS 10.1.16 and 10.1.21 are affected.
References
Configurations
No configuration.
History
23 Oct 2026, 14:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-10-23 14:17
Updated : 2026-10-28 20:18
NVD link : CVE-2026-93627
Mitre link : CVE-2026-93627
CVE.ORG link : CVE-2026-93627
JSON object : View
Products Affected
No product.
CWE
CWE-290
Authentication Bypass by Spoofing
