CVE-2026-93627 — MEDIUM (5.3)

Vulnerability 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 An attacker who knows the meeting UID and organizer address can supply a non-outdated sequence number to move the recipient's meeting to Trash or replace its details.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.

CVSS Score

5.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

LOW

Availability

NONE

Related Weaknesses (CWE)

CWE-290

References

FAQ

What is CVE-2026-93627?

CVE-2026-93627 is a vulnerability with a CVSS score of 5.3 (MEDIUM). 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...

How severe is CVE-2026-93627?

CVE-2026-93627 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-93627?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.