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.

CVSS 3.1

6.1CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS

20% chance of exploitation in the next 30 days; higher than 97% of CVEs (scores of 2026-10-25)

CISA KEV

listed 2026-03-18, due 2026-04-01

CWE

CWE-79

Published

2026-01-05

Modified

2026-10-07

Record from

the NVD, synced 2026-10-19

Affected

• synacor:zimbra_collaboration_suite

References

• https://wiki.zimbra.com/wiki/Security_Center
• 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://wiki.zimbra.com/wiki/Zimbra_Security_Advisories

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