PYSEC-2026-41

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.8 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

• CVE-2026-44827: 0.72% estimated exploitation activity in the next 30 days; percentile 53.91 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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…

Published by the source

14 May 2026, 17:16 UTC

Last modified by the source

20 May 2026, 09:18 UTC

Source last checked

24 Oct 2026, 04:13 UTC

1. Revision 1 · created · 24 Oct 2026

   Published from osv record PYSEC-2026-41

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# Patch Next advisory brief: CVE-2026-44827

Advisory: PYSEC-2026-41
IDs: CVE-2026-44827, GHSA-j7w6-vpvq-j3gm
Record: https://patchnext.com/advisories/cve-2026-44827 (revision 1, source checked 24 Oct 2026, 04:13 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: diffusers 0.38.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI diffusers: affected < 0.38.0; fixed in 0.38.0

## Suggested inspection (read-only)
- `python -m pip show diffusers`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on diffusers.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/PYSEC-2026-41 (OSV record PYSEC-2026-41 lists affected ranges: PyPI diffusers >=0 <0.38.0 (fixed))

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