← CVE catalog

CVE-2025-66376

High CVSS 7.2 Known exploited

Published 2026-01-05 · last changed 2026-06-17 · added to CISA KEV 2026-03-18

This one is being exploited in the wild.

CISA added CVE-2025-66376 to the Known Exploited Vulnerabilities catalog on 2026-03-18. Federal agencies are required to remediate it on a deadline. If you have affected machines, this is the class of finding that moves ahead of the rest of the queue.

The fix

We hold no Microsoft remediation data for CVE-2025-66376, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

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.

Sources

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