Running untrusted code can lead to security breaches, such as data theft or system compromise. To mitigate these risks, developers can use sandboxing techniques that isolate and restrict the execution environment. Tools like Docker can provide containerized environments with controlled resources and permissions. Python’s restricted execution mode, while deprecated, illustrates the need for secure execution practices. Additionally, use of languages or frameworks that inherently support sandboxing, like PyPy, can provide safer execution environments. Always validate and sanitize any external inputs used in code execution.