Jenkins 2.441 and earlier, LTS 2.426.2 and earlier does not disable a feature of its CLI command parser that replaces an '@' character followed by a file path in an argument with the file's contents, allowing unauthenticated attackers to read arbitrary files on the Jenkins controller file system.
Jenkins < 2.452.4 and < 2.471 - Arbitrary File Read via ClassLoaderProxy#fetchJar
Jenkins 2.470 and earlier, LTS 2.452.3 and earlier allows agent processes to read arbitrary files from the Jenkins controller file system by using the `ClassLoaderProxy#fetchJar` method in the Remoting library.