CVE-2026-73571 Missing authorization in Collaboration

Low 3.1 Published 13 Aug 2026 Updated 13 Aug 2026

Authenticated attackers can bypass delegation checks to impersonate users and send emails via crafted SOAP requests in Zimbra Collaboration.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-73571?

CVE-2026-73571 is a low-severity missing authorization vulnerability in Synacor Zimbra Collaboration Suite, published on 13 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official 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.

Weakness: CWE-863

Which versions are affected by CVE-2026-73571?

It affects 1 product.

Products include Synacor Zimbra Collaboration Suite.

How do I fix CVE-2026-73571?

No fix has been published for CVE-2026-73571 yet. Limit exposure of the affected software until one is available.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-73571 being exploited?

There is no known exploitation of CVE-2026-73571 in the wild and no public exploit code.

All Synacor Zimbra Collaboration Suite vulnerabilities

Sources

Also known as GHSA-p856-mgqw-j9rq.