Jenkins Convert To Pipeline Plugin 1.0 and earlier uses basic string concatenation to convert Freestyle projects' Build Environment, Build Steps, and Post-build Actions to the equivalent Pipeline step invocations, allowing attackers able to configure Freestyle projects to prepare a crafted configuration that injects Pipeline script code into the (unsandboxed) Pipeline resulting from a convertion by Jenkins Convert To Pipeline Plugin.

A cross-site request forgery (CSRF) vulnerability in Jenkins Convert To Pipeline Plugin 1.0 and earlier allows attackers to create a Pipeline based on a Freestyle project, potentially leading to remote code execution (RCE).