CVE-2026-73572: Synacor Zimbra Collaboration Suite

Medium severity, CVSS 6.1. EPSS: 0.3% chance of exploitation in the next 30 days.

In Zimbra Collaboration (ZCS) before 10.1.17, a stored cross-site scripting (XSS) vulnerability exists in the Zimbra Classic Web Client due to insufficient sanitization of specific attachment content during inline preview. An attacker can send a crafted email containing a malicious attachment that, when previewed by a user, executes arbitrary JavaScript within the victim's browser session. Successful exploitation may allow an attacker to perform unauthorized actions on behalf of the victim user, potentially leading to data exfiltration or unauthorized access to sensitive information.

Affected products

• Synacor Zimbra Collaboration Suite: before 10.1.17 (fixed in 10.1.17)

Published 2026-08-13. Last modified 2026-08-28.