CVE-2026-93627 Zimbra Collaboration Suite Calendar Processing Authentication Bypass via Forged iCalendar CANCEL/REQUEST Organizer
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-93627?
CVE-2026-93627 is a medium-severity vulnerability in Zimbra Collaboration Suite, published on 23 Oct 2026.
Official description
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 An attacker who knows the meeting UID and organizer address can supply a non-outdated sequence number to move the recipient's meeting to Trash or replace its details.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.
Weakness: CWE-290
Which versions are affected by CVE-2026-93627?
How do I fix CVE-2026-93627?
No fix has been published for CVE-2026-93627 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-93627 being exploited?
There is no known exploitation of CVE-2026-93627 in the wild and no public exploit code.
Sources
Also known as GHSA-77gq-8m6p-2c3g.