CVE-2026-93642

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BaseFortify

Publication date: 2026-09-25

Last updated on: 2026-09-29

Assigner: Rapid7, Inc.

Description

An unauthenticated sender can forge a share notification that triggers stored XSS when a signed-in Zimbra Modern recipient clicks Accept Share, allowing the attacker to access mailbox data and act as the victim.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-09-25

Last Modified

2026-09-29

Generated

2026-10-16

AI Q&A

2026-09-25

EPSS Evaluated

2026-10-14

NVD

CVE-2026-93642

EUVD

EUVD-2026-87099

Affected Vendors & Products

Vendor	Product	Version / Range
Zimbra	Zimbra	Collaboration Suite (ZCS) 0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-79	The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Attack-Flow Graph

Executive Summary

This vulnerability allows an unauthenticated attacker to send a forged share notification to a Zimbra Modern user. When the victim clicks Accept Share, it triggers a stored cross-site scripting (XSS) attack. This enables the attacker to access the victim's mailbox data and perform actions on their behalf.

Detection Guidance

Detection of this vulnerability requires monitoring for suspicious share notifications or XSS payloads in Zimbra Modern. Check mail server logs for unusual share requests or clicks on shared items. No specific commands are provided in the context.

Impact Analysis

If you use Zimbra Modern, an attacker could steal your emails, send messages as you, or access sensitive data in your mailbox. The attack requires you to click Accept Share, but once done, the attacker gains significant control over your account.

Compliance Impact

This vulnerability could lead to unauthorized access to personal or health data, violating GDPR and HIPAA requirements for data protection and confidentiality. Organizations using Zimbra Modern may face compliance breaches if exploited.

Mitigation Strategies

Update Zimbra Modern to the latest patched version immediately to address the stored XSS vulnerability in share notifications. Disable share notification features if not required until patched. Monitor for unusual activity in mailbox access logs.

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