CVE-2026-93634

Medium

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.

SeverityMedium
CVSS4.3
Exploit probability—
ProductSynacor Zimbra Collaboration Suite
PublishedOct 23, 2026
First seenOct 23, 2026

How to fix

Affected products

ProductAffected versionsFixed in
synacor zimbra_collaboration_suitev ≤ 10.1.20—

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