CVE-2026-73571

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 c

Zimbra CollaborationApplications & CMS

CVSS

3.1Low

ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV

Exploit odds (EPSS)0.26%Chance of exploitation activity in the next 30 days, higher than 16% of CVEs. Scored 23 Oct 2026FIRST EPSS

Fixed in10.1.17Fixed versionCVE List

Published13 Aug 2026Updated 13 Aug 2026CVE List

What fixes it

10.1.17CollaborationCVE List

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Timeline

13 Aug 2026, 15:20 UTCPublishedCVE List
14 Oct 2026, 13:00 UTCExploit code publicRapid7

Reports 1

1 outlet mention it. Reports are not confirmation; each links to its source.

From One Account to Every Mailbox: Breaking Zimbra's Identity Boundaries (Part 1)Rapid7, 14 Oct 2026Exploit code

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.

Text from CVE List

Affected versions 1

Collaborationaffected: all versions before 10.1.17CVE List