NetBox Device Type Library is a collection of community-sourced device type definitions for import into NetBox. The validation test harness can deserialize pull-request-controlled tracked pickle cache files through pickle.load in the read_pickle_data function in tests/pickle_operations.py. An unauthenticated contributor can change USE_LOCAL_KNOWN_SLUGS in tests/test_configuration.py and supply a crafted tests/known-modules.pickle or tests/known-racks.pickle file that tests/definitions_test.py loads when pytest runs. Deserialization invokes attacker-controlled object reduction behavior, allowing arbitrary code execution in the GitHub Actions runner or in a maintainer process that runs the tests, with the confidentiality, integrity, and availability of reachable resources at risk. This vulnerability is fixed with commit 1c6f7e2b93589b965318c6e67ac3504831f0e71e.