CVE-2026-93641

CRITICAL 9.3

Zimbra Collaboration Suite Classic Web Client Stored Cross-Site Scripting via Forged Share Invitation

CVSS Score

9.3

EPSS Score

0.0%

EPSS Percentile

0th

An unauthenticated sender can forge a share notification that triggers stored XSS when a signed-in Zimbra Classic recipient clicks Accept Share, allowing the attacker to access mailbox data and act as the victim.

CWE	CWE-79
Vendor	zimbra
Product	zimbra collaboration suite (zcs)
Published	Sep 25, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

Affected Versions

Zimbra / Zimbra Collaboration Suite (ZCS)

0 < 10.1.21

References

NVD ↗ CVE.org ↗ EPSS Data ↗

wiki.zimbra.com: https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories

Credits

Jonah Burgess (CryptoCat), Senior Security Researcher, Rapid7