CVE-2026-93627
Zimbra Collaboration Suite Calendar Processing Authentication Bypass via Forged iCalendar CANCEL/REQUEST Organizer
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CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Attack conditions and impact
Derived from the CNA (via NVD) CVSS 3.1 vectorThis vulnerability may be exploitable over the internet without authentication or user interaction.
| Metric | Value | Meaning |
|---|---|---|
| Attack vector AV | N | Network |
| Attack complexity AC | L | Low (easy) |
| Privileges required PR | N | None |
| User interaction UI | N | None |
| Scope S | U | Unchanged |
| Confidentiality C | N | None |
| Integrity I | L | Low |
| Availability A | N | None |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
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 An attacker who knows the meeting UID and organizer address can supply a non-outdated sequence number to move the recipient's meeting to Trash or replace its details.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 assessments
| Provider | Version | Score | Vector |
|---|---|---|---|
| NVD / [email protected] (Secondary) | 3.1 | 5.3 MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| CNA / rapid7 | 3.1 | 5.3 MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
Affected products and packages
CNA (CVE.org)
| Vendor | Product | Versions |
|---|---|---|
| Zimbra | Zimbra Collaboration Suite | affected: 0 … <= 10.1.21 default: unaffected |
Linux distribution status
References (2)
- https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories NVD, CNA vendor-advisory
- https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/ NVD, CNA related