Apache Karaf kar deployer reads .kar archives and extracts the paths from the "repository/" and "resources/" entries in the zip file. It then writes out the content of these paths to the Karaf repo and resources directories. However, it doesn't do any validation on the paths in the zip file. This means that a malicious user could craft a .kar file with ".." directory names and break out of the directories to write arbitrary content to the filesystem. This is the "Zip-slip" vulnerability - https://snyk.io/research/zip-slip-vulnerability. This vulnerability is low if the Karaf process user has limited permission on the filesystem. Any Apache Karaf releases prior 4.2.3 is impacted.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.