Zimbra Zero-Day Exploited to Target Brazilian Military via Malicious ICS Files

A now patched security vulnerability in Zimbra Collaboration was exploited as a zero-day earlier this year in cyber attacks targeting the Brazilian military. Tracked as CVE-2025-27915 CVSS score: 5.4, the vulnerability is a stored cross-site scripting XSS vulnerability in the Classic Web Client...

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...