CVE-2025-66376

MEDIUM CISA KEV EPSS 95.6%
Published Jan 5, 20265mo ago · Modified Jun 17, 20261w ago
6.1 CVSS 3.1
Medium
Find Similar
Published Jan 5, 2026 5mo ago
Last Modified Jun 17, 2026 1w ago
KEV Listed Mar 18, 2026 3mo ago
KEV Due Apr 1, 2026 90d overdue

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.

CVSS Details

Base Score
6.1
Exploitability
2.8
Impact
2.7
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction Required
Scope Changed
Confidentiality Low
Integrity Low
Availability None

Threat Intelligence

CISA Known Exploited Overdue 90d
Added
Mar 18, 2026
Due
Apr 1, 2026

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

EPSS Exploit Probability
95.6% percentile
Exploit & Patch Status
Actively Exploited (KEV)
No Patch Available

Weaknesses 1

CWE-79 Cross-site Scripting Injection

Affected Products 2

VendorProductVersionRange
synacorzimbra_collaboration_suite*≥10.0.0  –  <10.0.18
synacorzimbra_collaboration_suite*≥10.1.0  –  <10.1.13

References 6

  • wiki.zimbra.com https://wiki.zimbra.com/wiki/Security_Center
    Release NotesVendor Advisory
  • wiki.zimbra.com https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.18#Security_Fixes
    Release Notes
  • wiki.zimbra.com https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.13#Security_Fixes
    Release Notes
  • wiki.zimbra.com https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy
    Product
  • wiki.zimbra.com https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
    Vendor Advisory
  • cisa.gov https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-66376
    US Government Resource

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.