# CVE-2025-66376

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.

- Page: https://www.vulneraibility.com/cve/CVE-2025-66376
- CVSS: 7.2
- Known exploited: yes, in CISA KEV since 2026-03-18; CISA due date 2026-04-01
- EPSS: 20.23%
- CISA SSVC: exploitation active, automatable no, technical impact partial (assessed 2026-03-17)
- Weakness: CWE-79
- Published: 2026-01-05

## Affected versions

- Zimbra Collaboration: affected >= 10.0 and < 10.0.18; >= 10.1 and < 10.1.13

A version outside these ranges is not a statement that it is unaffected.

## References

- [other] https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
- [other] https://wiki.zimbra.com/wiki/Security_Center
- [other] https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy
- [other] https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.13#Security_Fixes
- [other] https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.18#Security_Fixes
- [other] https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-66376

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.