CVE-2025-27915
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.
CVSS Details
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Threat Intelligence
- Added
- Oct 7, 2025
- Due
- Oct 28, 2025
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Weaknesses 1
Affected Products 47
| Vendor | Product | Version | Range |
|---|---|---|---|
| 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 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
| synacor | zimbra_collaboration_suite | 9.0.0 | any |
References 6
- strikeready.com https://strikeready.com/blog/0day-ics-attack-in-the-wild/
- wiki.zimbra.com https://wiki.zimbra.com/wiki/Security_Center
- wiki.zimbra.com https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.13#Security_Fixes
- wiki.zimbra.com https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.5#Security_Fixes
- wiki.zimbra.com https://wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P44#Security_Fixes
- cisa.gov https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-27915
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.