{"id":"PYSEC-2026-40","details":"Diffusers is the a library for  pretrained diffusion models. Prior to 0.38.0, a trust_remote_code bypass in DiffusionPipeline.from_pretrained allows arbitrary remote code execution despite the user passing trust_remote_code=False (or omitting it, which is the default). The vulnerability has three variants, all sharing the same root cause — the trust_remote_code gate was implemented inside DiffusionPipeline.download() rather than at the actual dynamic-module load site, so any code path that bypassed or short-circuited download() also bypassed the security check. DiffusionPipeline.from_pretrained('repoA', custom_pipeline='attacker/repoB', trust_remote_code=False) — the gate evaluated against repoA's file list rather than repoB's, so repoB's pipeline.py was loaded and executed. DiffusionPipeline.from_pretrained('/local/snapshot', custom_pipeline='attacker/repoB', trust_remote_code=False) — the local-path branch never invoked download(), so the gate was never reached and remote code from repoB executed. DiffusionPipeline.from_pretrained('/local/snapshot', trust_remote_code=False) where the snapshot contains custom component files (e.g. unet/my_unet_model.py) referenced from model_index.json — same root cause; the local path skipped download() and custom component code executed. This vulnerability is fixed in 0.38.0.","aliases":["CVE-2026-44513","GHSA-98h9-4798-4q5v"],"modified":"2026-05-20T09:18:56.669156Z","published":"2026-05-14T17:16:22.903Z","references":[{"type":"EVIDENCE","url":"https://github.com/huggingface/diffusers/security/advisories/GHSA-98h9-4798-4q5v"}],"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-2026-40.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"}]}