Description
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.
Remediation
References
https://github.com/micronaut-projects/micronaut-core/security/advisories/GHSA-cjx7-399x-p2rj
https://github.com/micronaut-projects/micronaut-core/commit/a0cfeb13bf1ef5d692d16d4a3b91b34b7456bb11