CVE-2026-103088: Jknack Handlebars.java

High severity, CVSS 7.5. EPSS: 0.7% chance of exploitation in the next 30 days.

Handlebars.java before 4.5.5 allows directory traversal. In handlebars-springmvc 4.5.3 and 4.5.4, the path-containment fix for CVE-2026-63490 validates template locations as raw percent-encoded strings, whereas the template file is opened through a URL handler that percent-decodes the path. In a Spring MVC application with a file: template prefix and a request-derived view name, a percent-encoded traversal such as %2e%2e/ bypasses both the view-resolver check and the loader-side containment and reads files outside the configured template base directory.

Affected products

• Jknack Handlebars.java: from 4.5.3, before 4.5.5 (fixed in 4.5.5)

Published 2026-09-30. Last modified 2026-09-30.