Micronaut is a JVM-based, full stack Java framework designed for building JVM applications. A path traversal vulnerability exists in versions prior to 2.5.9. With a basic configuration, it is possible to access any file from a filesystem, using "/../../" in the URL. This occurs because Micronaut does not restrict file access to configured paths. The vulnerability is patched in version 2.5.9. As a workaround, do not use `**` in mapping, use only `*`, which exposes only flat structure of a directory not allowing traversal. If using Linux, another workaround is to run micronaut in chroot.

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in micronaut-core