Apache Hadoop’s RunJar.run() does not set permissions for temporary directory by default. If sensitive data will be present in this file, all the other local users may be able to view the content. This is because, on unix-like systems, the system temporary directory is shared between all local users. As such, files written in this directory, without setting the correct posix permissions explicitly, may be viewable by all other local users.
https://lists.apache.org/thread/xlo7q8kn4tsjvx059r789oz19hzgfkfs