CVE-2019-1003041: Sandbox bypass vulnerability in Jenkins Pipeline: Groovy Plugin

The vulnerability stems from insufficient sandbox validation during type coercion operations. The pre-patch version of CpsWhitelist.java's permitsStaticMethod explicitly allowed ScriptBytecodeAdapter.asType() calls (used for Groovy type casting) without performing security checks. This let attackers bypass sandbox restrictions by using Groovy's casting syntax (e.g., 'X as Y' or 'Y x = [...]') to invoke dangerous constructors. The patch added Checker.preCheckedCast() validation to enforce security restrictions during these operations, confirming this was the vulnerable code path.