CVE-2026-93641

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Stored XSS in Zimbra Classic Web Client

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 Classic recipient clicks Accept Share, allowing the attacker to access mailbox data and act as the victim.

CVSS Scores

EPSS Scores

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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-2026-93641

EUVD

EUVD-2026-87098

Affected Vendors & Products

Vendor	Product	Version / Range
zimbra	zimbra_collaboration	10.0.16
zimbra	zimbra_collaboration	10.1.10

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 Classic user. When the victim clicks 'Accept Share', it triggers a stored cross-site scripting (XSS) attack. This gives the attacker access to the victim's mailbox data and the ability to act as the victim.

Impact Analysis

If you use Zimbra Classic, an attacker could steal your emails, contacts, or other sensitive data. They could also send emails or perform actions on your behalf, potentially leading to further breaches or misuse of your account.

Compliance Impact

This vulnerability could lead to unauthorized access to personal or sensitive data, violating GDPR's data protection principles and HIPAA's security rules. Organizations may face fines or legal consequences for failing to protect user data adequately.

Mitigation Strategies

Apply the latest Zimbra security patches immediately to address the stored XSS vulnerability in share notifications. Disable or restrict share notification features if not required. Monitor mailbox activity for suspicious actions and educate users to avoid clicking on unexpected share requests.

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