Stored XSS Vulnerability in Zimbra Classic by Zimbra
CVE-2026-93641

9.3CRITICAL

Key Information:

Vendor

Zimbra

Status
Zimbra Collaboration Suite (zcs)
Vendor
CVE Published:
25 September 2026

What is CVE-2026-93641?

An unauthenticated sender can exploit a vulnerability in Zimbra Classic by sending a forged share notification. When a signed-in recipient accepts the share, it triggers stored XSS, allowing the attacker to execute malicious scripts. This compromises the mailbox data and permits unauthorized actions as if they were the victim, posing significant risks to user security and data integrity.

Affected Version(s)

Zimbra Collaboration Suite (ZCS) 0 < 10.1.21

References

https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
vendor-advisory

CVSS V3.1

Score:
9.3
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Jonah Burgess (CryptoCat), Senior Security Researcher, Rapid7
.