CVE-2025-66376
HIGH severity · CVSS 7.2 · Cross-site scripting (XSS) · actively exploited (CISA KEV)
7.2CVSS HIGH exploited
Actively exploited in the wild (CISA Known Exploited Vulnerabilities).
Added to KEV 2026-03-18. US federal agencies must patch by 2026-04-01.
Summary
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.
Impact & exploitability
Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
Confidentiality impactLow
Integrity impactLow
Availability impactNone
Exploit probability (EPSS)12%
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Affected products we track (1)
Recommendation
This vulnerability is being actively exploited in the wild — patch affected products urgently. Open any affected product above for its exact safe version.
Additional information
- NVD record
- https://wiki.zimbra.com/wiki/Security_CenterAdvisory
- https://wiki.zimbra.com/wiki/Zimbra_Security_AdvisoriesAdvisory
- https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.18#Security_Fixes
- https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.13#Security_Fixes
- https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-66376