CVE-2026-93628 Details
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 An attacker who knows the meeting UID, organizer address and attendee address can send a non-outdated reply that changes the attendee's participation status in the organizer's calendar.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.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Oct 28, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories | [email protected] | |
| https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/ | [email protected] |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-290 | Authentication Bypass by Spoofing | [email protected] |
Affected Products
No affected product data is available for this CVE.
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Oct 28, 2026 | CVE Modified | CISA-ADP |
| Oct 23, 2026 | New CVE Received | [email protected] |