What is GHSA-8563-28f8-ph7v?

GHSA-8563-28f8-ph7v is a security advisory published by GitHub Security Advisories with Medium severity. A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an...

Which CVE IDs does GHSA-8563-28f8-ph7v cover?

GHSA-8563-28f8-ph7v covers the following CVE IDs: CVE-2026-93634. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of GHSA-8563-28f8-ph7v?

GHSA-8563-28f8-ph7v has a CVSS v3 base score of 4.3, published by GitHub Security Advisories.

GHSA-8563-28f8-ph7vMediumCVSS 4.3

A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an...

Vendor

GitHub Security Advisories

Published

October 23, 2026

Last Modified

October 23, 2026

🔗 CVE IDs covered (1)

CVE-2026-93634 →

📋 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.

🔗 References (4)

https://nvd.nist.gov/vuln/detail/CVE-2026-93634
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1
https://github.com/advisories/GHSA-8563-28f8-ph7v