CVE-2025-66376 Synacor — Exploit & Vulnerability Details HIGH

CVE-2025-66376

HIGH CVSS 3.1: 6.1 EPSS 11.4% ACTIVE EXPLOIT

Parameter	Value
CVSS	6.1 (HIGH)
Affected Versions	10.0.0 — 10.1.13
Fixed In	10.0.18
Type	CWE-79 (Cross-Site Scripting (XSS))
Vendor	Synacor
Public PoC	Yes

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.

Attack Parameters

Attack Vector

Network

Can be exploited remotely

Attack Complexity

Low

Easy to exploit

Privileges Required

None

No privileges needed

User Interaction

Required

User action required

Impact Assessment

Confidentiality

Low

Partial data leak

Integrity

Low

Partial data modification

Availability

None

No disruption

CVSS Vector v3.1

Weakness Type (CWE)

CWE-79 Cross-Site Scripting (XSS)

Vulnerable Products 2

Configuration	From (including)	Up to (excluding)
Synacor Zimbra_Collaboration_Suite cpe:2.3:a:synacor:zimbra_collaboration_suite::::::::	`10.0.0`	`10.0.18`
Synacor Zimbra_Collaboration_Suite cpe:2.3:a:synacor:zimbra_collaboration_suite::::::::	`10.1.0`	`10.1.13`