Vulnerability Report

CVE-2025-66376

CISA KEV Active

Title: Classic UI stored XSS in Zimbra Collaboration (ZCS) via CSS @import directives

XSS

Proof Of Concept

No public PoC currently indexed for CVE-2025-66376.

CWE Category CWE-79
Published Date Jan 05, 2026
Modified Date Mar 18, 2026
Exploit Status Not Found
Score 7.2 CVSS v3.1
Exploit Probability (EPSS)
10.90%

Vulnerability Summary

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.

Impacted Vendors

S
synacor 1
Z
zimbra 1

Reference Links

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
CVSS v3.1
Source Entity [email protected]
Severity HIGH
7.2
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
6.1
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
REQUIRED
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2025-66376 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Affected Stack

No specific products linked.