CVEvulnerability

CVE-2025-27915

5.4 MEDIUM Known exploited Published 2025-03-12 Modified 2026-06-17 Official page ↗

CISA Known Exploited Vulnerability

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

Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting vulnerability that 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 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.

Added to KEV
2025-10-07
Remediation due
2025-10-28
Ransomware use
Unknown
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.
Notes
https://wiki.zimbra.com/wiki/Security_Center ; https://nvd.nist.gov/vuln/detail/CVE-2025-27915
Status
Analyzed
Published
2025-03-12
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 (134c704f-9b21-4f2e-91b3-4a467353bcc0)
5.4 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Weaknesses
CWE-79

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.

Affected configurations

• synacor zimbra collaboration suite (>= 10.0.0 < 10.0.13) • synacor zimbra collaboration suite (>= 10.1.0 < 10.1.5) • synacor zimbra collaboration suite 9.0.0

Related

Weakness · CWE (1)

  • CWE-79 Improper Neutralization of Input During Web Page Generation weakness

References