CISA KEV · Known exploitedMedium

CVE-2025-48700

Synacor Zimbra Collaboration Suite (ZCS)

An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0 and 10.0 and 10.1. A Cross-Site Scripting (XSS) vulnerability in the Zimbra Classic UI allows attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information. This issue arises from insufficient sanitization of HTML content, specifically involving crafted tag structures and attribute values that include an @import directive and other script injection vectors. The vulnerability is triggered when a user views a crafted e-mail message in the Classic UI,...

CVSS: 6.1
EPSS: 1.76%
CISA KEV: Listed
Published: 2025.06.24

PRIORITY ASSESSMENT

Immediate review

CISA has listed this vulnerability in the Known Exploited Vulnerabilities catalog.

Known exploitationConfirmed by CISA KEV

Exploit probability1.76%

Technical severityCVSS 6.1

Vulnerability overview

Affected product and versions

Product: Synacor Zimbra Collaboration Suite (ZCS)
Affected versions: >= 10.0.0 < 10.0.12, >= 10.1.0 < 10.1.4, 8.8.15, 9.0.0
Fixed versions: 10.0.12, 10.1.4

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

CISA required action

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

Due date: 2026.04.23

1
Identify
Confirm that Synacor Zimbra Collaboration Suite (ZCS) and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CWE: CWE-79
KEV added: 2026.04.20
Ransomware use: 미확인