CVE-2026-61398: Apache Cloudstack

Critical severity, CVSS 9.1. EPSS: 0.6% chance of exploitation in the next 30 days.

Improper Encoding or Escaping of Output vulnerability in Apache CloudStack's UI while using Instance Reset Password functionality. This issue affects Apache CloudStack: from 4.15.1.0 through 4.20.3.0 and from 4.21.0.0 through 4.22.1.0. Users are recommended to upgrade to version 4.20.3.1 or 4.22.1.1 or later, which fixes the issue.

Affected products

• Apache Cloudstack: from 4.15.1.0, before 4.20.3.1 (fixed in 4.20.3.1); from 4.21.0.0, before 4.22.1.1 (fixed in 4.22.1.1)

Published 2026-08-21. Last modified 2026-08-27.