Stored XSS Vulnerability in Zimbra Modern by Zimbra
CVE-2026-93642

9.3CRITICAL

Key Information:

Vendor

Zimbra

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

What is CVE-2026-93642?

An unauthenticated attacker can exploit a stored XSS vulnerability in Zimbra Modern by forging share notifications. When a signed-in recipient clicks 'Accept Share', the malicious payload executes, potentially allowing unauthorized access to mailbox data and enabling the attacker to impersonate the victim within the platform.

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
.