DataChain is a Python-based AI-data warehouse for transforming and analyzing unstructured data. Versions 0.34.1 and below allow for deseriaization of untrusted data because of the way the DataChain library reads serialized objects from environment variables (such as DATACHAIN__METASTORE and DATACHAIN__WAREHOUSE) in the loader.py module. An attacker with the ability to set these environment variables can trigger code execution when the application loads. This issue is fixed in version 0.34.2.