CVE-2025-27915
MEDIUM CISA KEVCVSS v3
5.4
MEDIUM
EPSS Score
—
exploit probability
CISA KEV
Yes
known exploited
Exploitation
—
SSVC status
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 suc
CISA Known Exploited Vulnerability
- Date Added
- 10/7/2025
- Patch Due Date
- 10/28/2025
- 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.
Technical Details
- CVSS v3 Vector
- 3.1
- Published
- 3/12/2025
- Last Modified
- 11/4/2025
Frequently Asked Questions
What is CVE-2025-27915?
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 suc
Is CVE-2025-27915 actively exploited?
Yes. CVE-2025-27915 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 10/28/2025.
What is the CVSS score for CVE-2025-27915?
CVE-2025-27915 has a CVSS v3 base score of 5.4 (MEDIUM severity), with vector string 3.1.
Is CVE-2025-27915 affecting your environment?
Use isMalicious to check if any of your IPs or domains are associated with this vulnerability's IOCs.