Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability. Actively exploited: CISA added this vulnerability to its Known Exploited Vulnerabilities catalog on 07/10/2025. Patch affected systems as an emergency.
| Package | Affected versions | Patched versions |
|---|---|---|
| zimbra collaboration suite | = 9.0.0≥ 10.0.0, < 10.0.13≥ 10.1.0, < 10.1.5 | 10.0.1310.1.5 |
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.
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