CVE-2025-48700KEV · OVERDUE

Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability

Medium · published June 23, 2025

Patch now

The score understates this — it's already being exploited

CVSS calls it medium at 6.1. It is confirmed in active exploitation. It sits in the 77.2th percentile for exploit probability.

184
days past CISA
deadline
CVSS v3.1
6.1
EPSS
2%
Percentile
77.2
In the wild
Confirmed
What it is

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, requiring no additional user interaction.

The record
Technical detail
CVSS v3.1
6.1 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.01713 · 77.2th percentile
Published
2025-06-23T00:00Z
KEV added
2026-04-20 · due 2026-04-23
EPSS history
Timeline
  • 20 APR 00:00Z
    Added to CISA KEV — remediate by Apr 23
    kev
  • 23 JUN 00:00Z
    An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0 and 10.0 and 10.1
    cvelistv5