The vulnerability stems from insecure credential persistence in XML configuration. Jenkins plugins typically use DescriptorImpl for global configuration storage, and the advisory explicitly mentions RocketChatNotifier.xml as the vulnerable file. The configure() method is the standard entry point for saving global configurations in Jenkins plugins, making it likely responsible for writing credentials without encryption. The presence of getPassword() method (common credential exposure pattern) would directly enable plaintext retrieval. While exact source code isn't available, Jenkins plugin conventions and the explicit file path/artifact names in advisories support these conclusions.