Jenkins Build-Publisher plugin version 1.21 and earlier stores credentials to other Jenkins instances in the file hudson.plugins.build_publisher.BuildPublisher.xml in the Jenkins master home directory. These credentials were stored unencrypted, allowing anyone with local file system access to access them. Additionally, the credentials were also transmitted in plain text as part of the configuration form. This could result in exposure of the credentials through browser extensions, cross-site scripting vulnerabilities, and similar situations.