CVE-2026-93631

A cross-site request forgery vulnerability in the OAuth extension of Zimbra Collaboration Suite (ZCS) Network Edition allows an attacker to link an attacker-controlled external account to a victim's mailbox. The OAuth callback does not bind its state value or authorization code to the initiating Zimbra session and instead selects the destination mailbox from the browser's current authentication cookie. On a deployment with the provider configured, an attacker can induce a signed-in victim to load a callback containing a fresh code for the attacker's provider account. This creates a persistent data source that imports attacker-controlled contacts or events. With bidirectional CalDAV synchronization, appointments subsequently created or edited in the linked calendar are also disclosed to the attacker. ZCS 10.1.16 and 10.1.20 are affected.

CVSS v3 7.1 HIGH

7.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 4.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

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, 21:27

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 21:27

NVD link : CVE-2026-93631

Mitre link : CVE-2026-93631

CVE.ORG link : CVE-2026-93631

JSON object : View

Products Affected

synacor

zimbra_collaboration_suite

CWE

CWE-352

Cross-Site Request Forgery (CSRF)

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