GHSA-386q-5hp3-95m9: `datamodel-code-generator` vulnerable to code injection in via attacker-controlled `default_factory` schema field

Summary datamodel-code-generator is vulnerable to code injection when generating Python models from an attacker-controlled JSON Schema, OpenAPI, YAML, JSON, Avro, Protobuf, or XSD schema. When a property carries a "default_factory" key, its value is interpolated verbatim — as a raw Python expression — into the generated Field(default_factory=...) / field(default_factory=...) call. Because this assignment is evaluated at class-definition time (i.e. on import of the generated module), an attacker who controls the schema controls a Python expression that runs in the consumer's process. No special CLI flags are required. Details The vulnerable chain spans the JSON-Schema-shaped parser and three sink locations (Pydantic v2, dataclass, msgspec): Source — schema → extras: - src/datamodel_code_generator/parser/jsonschema.py:600-614 — DEFAULT_FIELD_KEYS includes the literal string "default_factory". - src/datamodel_code_generator/parser/jsonschema.py:457-459 — JsonSchemaObject.init stores any non-standard key (including default_factory) in self.extras. - src/datamodel_code_generator/parser/jsonschema.py:797-812 — get_field_extras preserves default_factory through to the field model. Sinks — extras → generated Python expression: 1. src/datamodel_code_generator/model/pydantic_base.py:222-249: default_factory = data.pop("default_factory", None) ... if default_factory is not None: field_arguments = [f"default_factory={default_factory}", *field_arguments] The default_factory value is interpolated raw (no repr(), no validation). 2. src/datamodel_code_generator/model/dataclass.py:211: f"{k}={v if k == 'default_factory' else repr(v)}" Explicit special-case to skip repr() for default_factory. 3. src/datamodel_code_generator/model/msgspec.py:361 — same pattern as dataclass. Because default_factory is in DEFAULT_FIELD_KEYS, no special CLI flag is needed to reach the sink. Any input format that uses the JSON-Schema-shaped parser (jsonschema, openapi, yaml, json, dict, csv)