CVE-2026-93634

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.

CVSS v3 4.3 MEDIUM

4.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories	Vendor Advisory
https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/	Exploit Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*

History

28 Oct 2026, 21:21

Type	Values Removed	Values Added
References	~~() https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories -~~	() https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories - Vendor Advisory
References	~~() https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/ -~~	() https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/ - Exploit, Third Party Advisory
First Time		Synacor zimbra Collaboration Suite Synacor
CPE		cpe:2.3:a:synacor:zimbra_collaboration_suite::::::::

23 Oct 2026, 14:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-23 14:17

Updated : 2026-10-28 21:21

NVD link : CVE-2026-93634

Mitre link : CVE-2026-93634

CVE.ORG link : CVE-2026-93634

JSON object : View

Products Affected

synacor

zimbra_collaboration_suite

CWE

CWE-639

Authorization Bypass Through User-Controlled Key

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