CVE-2025-66376 HIGH

CVE-2025-66376

Vendor Zimbra
Product Collaboration
Weakness CWE-79 · XSS
KEV Status Known Exploited
Published January 5, 2026
Last update March 19, 2026
View on NVD All CVEs

CVSS base score

7.2/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality Low
Integrity Low

CVSS vector

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

What the vulnerability does

01Description

Zimbra Collaboration (ZCS) 10 before 10.0.18 and 10.1 before 10.1.13 allows Classic UI stored XSS via Cascading Style Sheets (CSS) @import directives in an HTML e-mail message.

CISA mandated remediation

02CISA Required Action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Key dates

03Disclosure timeline

January 5, 2026 CVE published
March 19, 2026 Record updated