Vulnerability Description
A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to insert forged shared-file records into another user's mailbox through FileSharedWithMeRequest. The request bypasses delegated-account authorization and accepts attacker-selected file metadata, owner identifiers and declared sizes without validating a corresponding document share. An attacker can plant entries attributed to another real local account without that account sharing a document. No victim interaction is required. ZCS 10.1.16 and 10.1.20 are affected.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Synacor | Zimbra Collaboration Suite | <= 10.1.20 |
Related Weaknesses (CWE)
References
- https://wiki.zimbra.com/wiki/Zimbra_Security_AdvisoriesVendor Advisory
- https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/ExploitThird Party Advisory
FAQ
What is CVE-2026-93634?
CVE-2026-93634 is a vulnerability with a CVSS score of 4.3 (MEDIUM). A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to insert forged shared-file records into another user's mailbox through FileSharedWithMeRe...
How severe is CVE-2026-93634?
CVE-2026-93634 has been rated MEDIUM with a CVSS base score of 4.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-93634?
Check the references section above for vendor advisories and patch information. Affected products include: Synacor Zimbra Collaboration Suite.