PYSEC-2026-40
Vulnerability from pysec - Published: 2026-05-14 17:16 - Updated: 2026-05-20 09:18Diffusers 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.
| Name | purl | diffusers | pkg:pypi/diffusers |
|---|
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "diffusers",
"purl": "pkg:pypi/diffusers"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.38.0"
}
],
"type": "ECOSYSTEM"
}
],
"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"
]
}
],
"aliases": [
"CVE-2026-44513",
"GHSA-98h9-4798-4q5v"
],
"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 \u2014 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(\u0027repoA\u0027, custom_pipeline=\u0027attacker/repoB\u0027, trust_remote_code=False) \u2014 the gate evaluated against repoA\u0027s file list rather than repoB\u0027s, so repoB\u0027s pipeline.py was loaded and executed. DiffusionPipeline.from_pretrained(\u0027/local/snapshot\u0027, custom_pipeline=\u0027attacker/repoB\u0027, trust_remote_code=False) \u2014 the local-path branch never invoked download(), so the gate was never reached and remote code from repoB executed. DiffusionPipeline.from_pretrained(\u0027/local/snapshot\u0027, trust_remote_code=False) where the snapshot contains custom component files (e.g. unet/my_unet_model.py) referenced from model_index.json \u2014 same root cause; the local path skipped download() and custom component code executed. This vulnerability is fixed in 0.38.0.",
"id": "PYSEC-2026-40",
"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"
}
],
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
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