CVE-2026-103088 Path traversal in handlebars.java
Attackers can read arbitrary files outside the template directory in Spring MVC apps using Handlebars.java with file-based templates.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-103088?
CVE-2026-103088 is a high-severity path traversal vulnerability in jknack handlebars.java, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-24
Which versions are affected by CVE-2026-103088?
How do I fix CVE-2026-103088?
No fix has been published for CVE-2026-103088 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-103088 being exploited?
There is no known exploitation of CVE-2026-103088 in the wild and no public exploit code.
Sources
Also known as GHSA-2m6h-5wp5-qp66, GHSA-pvrx-3g7m-fpgv.