Cross-Account Authorization Vulnerability in Zimbra Collaboration Suite
CVE-2026-93634

4.3MEDIUM

Key Information:

Vendor

Zimbra

Status
Zimbra Collaboration Suite
Vendor
CVE Published:
23 October 2026

What is CVE-2026-93634?

The Zimbra Collaboration Suite is susceptible to a cross-account authorization vulnerability that allows an authenticated user to exploit FileSharedWithMeRequest. This flaw enables attackers to inject malicious shared-file records into another user's mailbox without proper authorization checks. By bypassing delegated-account permissions, the attacker can manipulate file metadata and owner identifiers, resulting in unauthorized file entries being displayed in a victim's inbox. The affected versions, ZCS 10.1.16 and 10.1.20, do not require any interaction from the victim, making this vulnerability particularly concerning for user data integrity.

Affected Version(s)

Zimbra Collaboration Suite 0 <= 10.1.20

References

https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
vendor-advisory
https://www.rapid7.com/blog/post/ve-breaking-zimbra-ident...
related

CVSS V3.1

Score:
4.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Jonah Burgess (CryptoCat), Senior Security Researcher, Rapid7
.