CVE-2025-27915

5.4 MEDIUM CISA KEV - Actively Exploited
Published: March 12, 2025 Modified: November 04, 2025

Description

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1. A stored cross-site scripting (XSS) vulnerability exists in the Classic Web Client due to insufficient sanitization of HTML content in ICS files. When a user views an e-mail message containing a malicious ICS entry, its embedded JavaScript executes via an ontoggle event inside a <details> tag. This allows an attacker to run arbitrary JavaScript within the victim's session, potentially leading to unauthorized actions such as setting e-mail filters to redirect messages to an attacker-controlled address. As a result, an attacker can perform unauthorized actions on the victim's account, including e-mail redirection and data exfiltration.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://wiki.zimbra.com/wiki/Security_Center
Source: cve@mitre.org
Release Notes
https://strikeready.com/blog/0day-ics-attack-in-the-wild/
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Third Party Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-27915
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
US Government Resource

6 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.4 / 10.0
EPSS (Exploit Probability)
29.4%
96th percentile
Exploitation Status
Actively Exploited
Remediation due: 2025-10-28

Weaknesses (CWE)

Affected Vendors

synacor