# CVE-2026-93634: Zimbra Collaboration Suite cross-account authorization bypass in FileSharedWithMeRequest

Source: https://junglewise.ai/threats/cve-2026-93634-a-cross-account-authorization-vulnerability-in-zimbra  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-23. Updated: 2026-10-23  
License: CC BY 4.0 with a link back

CVE-2026-93634 · Severity: medium · CVSS 4.3 · Published 2026-10-23

Zimbra Collaboration Suite is an enterprise mail and collaboration platform that handles email, calendars, contacts, and file sharing. An authenticated attacker can forge file-sharing records in other users' mailboxes without their knowledge or consent, potentially exposing sensitive information or planting false evidence in victim accounts. No user interaction is required for the attack to succeed.

Technologies: [Zimbra Collaboration Suite](https://junglewise.ai/threats/technologies/collaboration). Vendors: [Zimbra](https://junglewise.ai/threats/vendors/zimbra).

## Quick answers

**Is CVE-2026-93634 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-93634 being exploited in the wild.

**How severe is CVE-2026-93634?** Medium severity, with a CVSS score of 4.3, published 23 October 2026.

**Which products and versions are affected?** Zimbra Collaboration Suite 10.1.16, 10.1.20.

**Is there a fix for CVE-2026-93634?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-93634 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-93634?** Check whether you run Zimbra Collaboration Suite at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in the FileSharedWithMeRequest handler, which fails to validate that a document share actually exists before accepting attacker-supplied file metadata, owner identifiers, and declared sizes. The flaw bypasses delegated-account authorization checks, allowing any authenticated user to inject forged shared-file records into arbitrary mailboxes. An attacker with a single compromised account can plant entries attributed to any other local account without their involvement or awareness.

## Affected products

- Zimbra Collaboration Suite 10.1.16, 10.1.20

## Timeline

- 2026-10-23: disclosed: Vulnerability published on NVD

## References

- [https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories](https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories)
- [https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/](https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/)

## Related threats

- [Zimbra Collaboration Suite local privilege escalation in dnscache](https://junglewise.ai/threats/cve-2026-93640-a-local-privilege-escalation-vulnerability-in-the-optional)
- [Zimbra Collaboration Suite authorization bypass in Zimlet configuration](https://junglewise.ai/threats/cve-2026-93639-a-missing-authorization-vulnerability-in-zimbra-collaboration)
- [Zimbra Collaboration Suite reflected cross-site scripting in login](https://junglewise.ai/threats/cve-2026-93638-a-reflected-cross-site-scripting-vulnerability-in-the-login-page)
- [Zimbra Collaboration Suite LDAP filter injection](https://junglewise.ai/threats/cve-2026-93636-an-ldap-filter-injection-vulnerability-in-zimbra-collaboration)
- [Zimbra Collaboration Suite CSS sanitization bypass](https://junglewise.ai/threats/cve-2026-93633-a-css-sanitization-vulnerability-in-zimbra-collaboration-suite)