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.
Affected products
synacor: zimbra collaboration suite
References2
- wiki.zimbra.com/wiki/Zimbra_Security_Advisories Vendor Advisory
- www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries… ExploitThird Party Advisory
Metrics
- CVSS 3.1
-
4.3
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - EPSS — exploit probability
- 0% percentile: 20 · as of 8 November 2026
- CWE
- CWE-639
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