CVE-2025-66376

7.2 HIGH CISA KEV - Actively Exploited

Published: January 05, 2026 Modified: March 18, 2026

Description

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.

AI Explanation

Get an AI-powered plain-language explanation of this vulnerability and remediation steps.

CVSS v3.x Details

0.0 Low Medium High Critical 10.0

Vector String

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

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory

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

Source: cve@mitre.org

Release Notes Vendor Advisory

https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.18#Security_Fixes

Source: cve@mitre.org

Release Notes

https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.13#Security_Fixes

Source: cve@mitre.org

Release Notes

https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy

Source: cve@mitre.org

Product

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

Source: cve@mitre.org

Vendor Advisory

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-66376

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

US Government Resource

6 reference(s) from NVD

Quick Stats

CVSS v3 Score

7.2 / 10.0

EPSS (Exploit Probability)

28.8%

96th percentile

Exploitation Status

Actively Exploited

Remediation due: 2026-04-01

Weaknesses (CWE)

CWE-79

Affected Vendors

synacor

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