What’s Vulnerable › Vulnerabilities

CVE-2026-73571

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-13 · updated 2026-08-28
• Weakness: CWE-863

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.

Affected products

• Zimbra Collaboration: before 10.1.17 — fixed in 10.1.17

How to fix

Upgrade to a fixed version: Zimbra Collaboration 10.1.17. Check the vendor advisory for mitigations.

In the news

• From One Account to Every Mailbox: Breaking Zimbra's Identity Boundaries (Part 1)

References

• https://wiki.zimbra.com/wiki/Security_Center
• https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories

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