AIKIDO-2026-610076

TL;DR

DynamicExpresso enforces a default reflection restriction through DisableReflectionVisitor, but lambda bodies are parsed by a second, internally-created Interpreter that never receives this visitor. An expression that uses InterpreterOptions.LambdaExpressions together with a dynamic parameter (LateBindObject or an IDynamicMetaObjectProvider value such as ExpandoObject) can therefore reach arbitrary reflection and OS command execution from inside a lambda, even though the identical expression is blocked at the top level. The fix moves visitor registration from the Interpreter instance into the shared, cloned ParserSettings, so lambda and nested-lambda parsing keep DisableReflectionVisitor enforced by default.