{"id":"PYSEC-2026-41","details":"Diffusers is the a library for  pretrained diffusion models. Prior to 0.38.0, diffusers 0.37.0 allows remote code execution without the trust_remote_code=True safeguard when loading pipelines from Hugging Face Hub repositories. The _resolve_custom_pipeline_and_cls function in pipeline_loading_utils.py performs string interpolation on the custom_pipeline parameter using f\"{custom_pipeline}.py\". When custom_pipeline is not supplied by the user, it defaults to None, which Python interpolates as the literal string \"None.py\". If an attacker publishes a Hub repository containing a file named None.py with a class that subclasses DiffusionPipeline, the file is automatically downloaded and executed during a standard DiffusionPipeline.from_pretrained() call with no additional keyword arguments. The trust_remote_code check in DiffusionPipeline.download() is bypassed because it evaluates custom_pipeline is not None as False (since the kwarg was never supplied), while the downstream code path that actually loads the module resolves the None value into a valid filename. An attacker can achieve silent arbitrary code execution by publishing a malicious model repository with a None.py file and a standard-looking model_index.json that references a legitimate pipeline class name, requiring only that a victim calls from_pretrained on the repository. This vulnerability is fixed in 0.38.0.","aliases":["CVE-2026-44827","GHSA-j7w6-vpvq-j3gm"],"modified":"2026-05-20T09:18:56.729581Z","published":"2026-05-14T17:16:23.500Z","references":[{"type":"EVIDENCE","url":"https://github.com/huggingface/diffusers/security/advisories/GHSA-j7w6-vpvq-j3gm"}],"affected":[{"package":{"name":"diffusers","ecosystem":"PyPI","purl":"pkg:pypi/diffusers"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.38.0"}]}],"versions":["0.0.1","0.0.2","0.0.3","0.0.4","0.1.0","0.1.1","0.1.2","0.1.3","0.10.0","0.10.1","0.10.2","0.11.0","0.11.1","0.12.0","0.12.1","0.13.0","0.13.1","0.14.0","0.15.0","0.15.1","0.16.0","0.16.1","0.17.0","0.17.1","0.18.0","0.18.1","0.18.2","0.19.0","0.19.1","0.19.2","0.19.3","0.2.0","0.2.1","0.2.2","0.2.3","0.2.4","0.20.0","0.20.1","0.20.2","0.21.0","0.21.1","0.21.2","0.21.3","0.21.4","0.22.0","0.22.1","0.22.2","0.22.3","0.23.0","0.23.1","0.24.0","0.25.0","0.25.1","0.26.0","0.26.1","0.26.2","0.26.3","0.27.0","0.27.1","0.27.2","0.28.0","0.28.1","0.28.2","0.29.0","0.29.1","0.29.2","0.3.0","0.30.0","0.30.1","0.30.2","0.30.3","0.31.0","0.32.0","0.32.1","0.32.2","0.33.0","0.33.1","0.34.0","0.35.0","0.35.1","0.35.2","0.36.0","0.37.0","0.37.1","0.4.0","0.4.1","0.4.2","0.5.0","0.5.1","0.6.0","0.7.0","0.7.1","0.7.2","0.8.0","0.8.1","0.9.0"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/diffusers/PYSEC-2026-41.yaml"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"}]}