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Fencer Intel
high 8.8

CVE-2026-44827 json

Diffusers: None.py Trust Remote Code Bypass

published 6mo ago modified 14d ago also GHSA-j7w6-vpvq-j3gm , PYSEC-2026-41 , EUVD-2026-30332

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 54%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi diffusers 0.38.0
  • huggingface diffusers 0.38.0

Is CVE-2026-44827 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-44827 updated cvss 8.8

diffusers: Diffusers: Arbitrary Code Execution via malicious model loading

  • Red Hat AI Inference Server rhaiis/vllm-tpu-rhel9
    affected: workaround, no fix planned “Will not fix”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-openvino-model-server-rhel9
    affected: workaround, no fix available
  • Red Hat AI Inference Server 3.4 rhaii/vllm-cpu-rhel9 1789681128, rhaii/vllm-cpu-rhel9 1790075793, rhaii/vllm-cuda-rhel9 1789681126, rhaii/vllm-cuda-rhel9 1790090131
    fixed: vendor fix RHSA-2026:69466
  • Red Hat Enterprise Linux AI 3.4 rhelai3/bootc-cuda-rhel9 1790868254, rhelai3/bootc-aws-cuda-rhel9 1790881122, rhelai3/bootc-gcp-cuda-rhel9 1790881123, rhelai3/disk-image-cuda-rhel9 1790957417, rhelai3/bootc-azure-cuda-rhel9 1790881120
    fixed: vendor fix RHSA-2026:76150
  • Red Hat OpenShift AI 3.4 rhoai/odh-th06-rocm64-torch291-py312-rhel9 1787076481, rhoai/odh-th06-cuda130-torch210-py312-rhel9 1787077779, rhoai/odh-training-rocm64-torch29-py312-rhel9 1786611435, rhoai/odh-training-cuda128-torch29-py312-rhel9 1786611803
    fixed: vendor fix RHSA-2026:60520
  • Red Hat AI Inference Server rhaiis/vllm-rocm-rhel9 Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-rocm-rhel9, rhelai3/bootc-azure-rocm-rhel9 Red Hat Enterprise Linux AI 3.4 rhelai3/bootc-rocm-rhel9 1790614447, rhelai3/bootc-azure-rocm-rhel9 1790707552
    not affected: vulnerable code not present
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-th06-cuda130-torch291-py312-rhel9
    not affected: component not present
  • Red Hat OpenShift AI 3.4 rhoai/odh-cli-rhel9 1787330837, rhoai/rhai-cli-rhel9 1787330837, rhoai/odh-automl-rhel9 1786612415, rhoai/odh-mlflow-rhel9 1787226790, rhoai/odh-autorag-rhel9 1786612637, rhoai/odh-trainer-rhel9 1787089049, +96 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
5mo ago

Exploit prediction

0.72% chance of exploitation in the next 30 days, higher than 54% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/huggingface/diffusers/security/advisories/GHSA-j7w6-vpvq-j3gm referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
OSV 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
pypi diffusers
<0.38.0
0.38.0

Affected products

  • huggingface diffusers

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.