---
id: CVE-2026-93634
title: >-
  Zimbra Collaboration Suite Cross-Account Authorization Bypass via Forged
  Shared-File Records
summary: >-
  A cross-account authorization vulnerability in Zimbra Collaboration Suite
  (ZCS) allows an authenticated user to insert forged shared-file records into
  another user's mailbox through FileSharedWithMeRequest. The request bypasses
  delegated…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N'
cvssSource: cna
cwe:
  - CWE-639
vendor: Zimbra
product: Zimbra Collaboration Suite
affected:
  - collaboration_suite <= 10.1.20
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T13:26:11.070Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-93634'
references:
  - url: 'https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories'
  - url: >-
      https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/
tags:
  - cve.org
ingestedAt: '2026-10-23T14:28:08.710Z'
---

## Overview

A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to insert forged shared-file records into another user's mailbox through FileSharedWithMeRequest. The request bypasses delegated-account authorization and accepts attacker-selected file metadata, owner identifiers and declared sizes without validating a corresponding document share. An attacker can plant entries attributed to another real local account without that account sharing a document. No victim interaction is required. ZCS 10.1.16 and 10.1.20 are affected.

## Affected

- `collaboration_suite <= 10.1.20`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.