CVE-2026-93629 Zimbra Collaboration Suite Calendar Processing Authentication Bypass via Forged iCalendar REQUEST Organizer Identity
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-93629?
CVE-2026-93629 is a medium-severity vulnerability in Zimbra Collaboration Suite, published on 23 Oct 2026.
Official description
An organizer authentication vulnerability in Zimbra Collaboration Suite (ZCS) allows an unauthenticated email sender to insert calendar invitations attributed to another user. The email delivery path permits external invitations but does not verify that the message sender is authorized to use the iCalendar ORGANIZER identity. When automatic invitation insertion is enabled, a crafted REQUEST component creates an event containing attacker-selected meeting details and reminders under a forged organizer without recipient interaction. No corresponding event is created in the claimed organizer's calendar. ZCS 10.1.16 and 10.1.21 are affected.
Weakness: CWE-290
Which versions are affected by CVE-2026-93629?
How do I fix CVE-2026-93629?
No fix has been published for CVE-2026-93629 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-93629 being exploited?
There is no known exploitation of CVE-2026-93629 in the wild and no public exploit code.
Sources
Also known as GHSA-x4qw-fpgg-g7x4.