CVE-2025-66376NVD

Vulnerability 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.

Severity Level

HIGH(7.2)

Published Date

Jan 5, 2026

Last Modified

Oct 7, 2026

Exploitation Status

ACTIVE

EPSS Score (30-Day)

20.23%Probability

Root Weakness (CWE)

CWE-79: Cross-site Scripting (XSS) ↗

The software does not neutralize user-controllable input before it is placed in output that is used as a web page.

CVSS v3.1 Base Metrics — Score 7.2 (HIGH)

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeChanged

ConfidentialityLow

IntegrityLow

AvailabilityNone

Affected & Patched Versions

Affected Versions

Synacor Zimbra Collaboration Suite >= 10.0.0 and < 10.0.18
Synacor Zimbra Collaboration Suite >= 10.1.0 and < 10.1.13

Patched Versions

Synacor Zimbra Collaboration Suite 10.0.18
Synacor Zimbra Collaboration Suite 10.1.13

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