CVE-2026-73571
LowCVSS 3.1Summary
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.
Risk Assessment
The risk includes the ability to impersonate other users and send emails on their behalf, which can lead to communication integrity breaches, fraud, or phishing. It can also undermine trust in the email system.
Recommendation
It is recommended to immediately upgrade Zimbra Collaboration to version 10.1.17 or later. Also thoroughly verify delegation and send-as permissions in SOAP request handling.
Original NVD description (English source)
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.