A sandbox bypass vulnerability exists in Pipeline: Groovy Plugin 2.61 and earlier in src/main/java/org/jenkinsci/plugins/workflow/cps/CpsFlowDefinition.java, src/main/java/org/jenkinsci/plugins/workflow/cps/CpsGroovyShellFactory.java that allows attackers with Overall/Read permission to provide a pipeline script to an HTTP endpoint that can result in arbitrary code execution on the Jenkins master JVM.