CVE-2026-44827 Diffusers: None.py Trust Remote Code Bypass
Attackers can execute arbitrary code by publishing a malicious None.py file in a Hugging Face repository, bypassing trust_remote_code safeguards in Diffusers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-44827?
CVE-2026-44827 is a high-severity code injection vulnerability in huggingface diffusers, published on 14 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-94
Which versions are affected by CVE-2026-44827?
3 open source packages ship an affected version, including diffusers. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
diffusers PyPI | All versions | 0.38.0 |
diffusers PyPI | All versions | 0.38.0 |
diffusers PyPI | All versions | 0.38.0 |
Products include Huggingface Diffusers.
How do I fix CVE-2026-44827?
Upgrade diffusers to 0.38.0 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-44827 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44827 exists.
Other vulnerabilities in huggingface diffusers
Sources
Also known as GHSA-j7w6-vpvq-j3gm, PYSEC-2026-41.