Zimbra Collaboration: CVE-2025-27915: This patch fixes a critical security vulnerability.

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.