CVE-2026-73571

Analyzed Analyzed - Analysis Complete

Authorization Bypass in Zimbra Collaboration via SOAP Request

Publication date: 2026-08-13

Last updated on: 2026-08-28

Assigner: MITRE

Description

An authorization bypass vulnerability exists in Zimbra Collaboration (ZCS) before 10.1.17 due to improper authorization validation in delegated email sending functionality. An authenticated attacker can send specially crafted SOAP requests to impersonate another user and send emails without possessing the required delegation or send-as permissions. This occurs in the SaveDraftRequest SOAP handler.

CVSS Scores

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Meta Information

Published

2026-08-13

Last Modified

2026-08-28

Generated

2026-09-03

AI Q&A

2026-08-13

EPSS Evaluated

2026-09-01

NVD

CVE-2026-73571

EUVD

EUVD-2026-58070

Affected Vendors & Products

Vendor	Product	Version / Range
synacor	zimbra_collaboration_suite	to 10.1.17 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-863	The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

Attack-Flow Graph

Executive Summary

This is an authorization bypass vulnerability in Zimbra Collaboration (ZCS) before version 10.1.17. It allows an authenticated attacker to send emails impersonating another user without proper delegation or send-as permissions by exploiting improper authorization validation in the SaveDraftRequest SOAP handler.

Detection Guidance

This vulnerability involves improper authorization validation in Zimbra Collaboration's SOAP requests. To detect it, monitor for unusual SOAP requests, particularly SaveDraftRequest operations, and verify that send-as permissions are correctly enforced. Check Zimbra logs for unauthorized email sending attempts or impersonation activities.

Impact Analysis

An attacker could send emails on your behalf, potentially tricking recipients into disclosing sensitive information or performing unauthorized actions. This could lead to reputational damage, data breaches, or further compromise of your account or systems.

Compliance Impact

The vulnerability allows unauthorized email sending by impersonating users, which could lead to unauthorized data disclosure or modification. This may violate GDPR's principles of data protection and integrity, and HIPAA's requirements for access controls and audit logging if email content contains protected health information.

Mitigation Strategies

Upgrade Zimbra Collaboration to version 10.1.17 or later to address the authorization bypass vulnerability in the SaveDraftRequest SOAP handler.

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