Diffusers: TOCTOU Trust Remote Code Bypass

Exploitation

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

CVSS

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

EPSS

• CVE-2026-45804: 0.37% estimated exploitation activity in the next 30 days; percentile 30.95 (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.

Background This vulnerability is found in the diffusers package - the transformers-equivalent library for diffusion models. It is found in the DiffusionPipeline.frompretrained flow, which is used to load a pipeline from the HuggingFace Hub. This function has a trustremotecode guard: if the repository’s modelindex.json references a custom pipeline class defined in a .py file in the repo, the load is blocked unless trustremotecode=True is explicitly passed: The vulnerability allows arbitrary code execution through the custom pipeline flow from a Hub repo, with no custompipeline or trustremotecode kwargs passed. The frompretrained call succeeds and returns a functional pipeline. --- Naive Flow DiffusionPipeline.frompretrained begins by popping all relevant arguments from kwargs into local variables, then calls DiffusionPipeline.download() to fetch the repo files: Inside download(), modelindex.json is fetched first as a standalone file via hfhubdownload: This config is used to detect…

Published by the source

20 May 2026, 15:31 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 13:49 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-7wx4-6vff-v64p

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-7wx4-6vff-v64p

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# Patch Next advisory brief: CVE-2026-45804

Advisory: Diffusers: TOCTOU Trust Remote Code Bypass
IDs: CVE-2026-45804, GHSA-7wx4-6vff-v64p
Record: https://patchnext.com/advisories/cve-2026-45804 (revision 2, source checked 26 Oct 2026, 13:49 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
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/GHSA-7wx4-6vff-v64p (OSV record GHSA-7wx4-6vff-v64p lists affected ranges: PyPI diffusers >=0 <0.38.0 (fixed))
- Verified: https://github.com/advisories/GHSA-7wx4-6vff-v64p (GitHub-reviewed advisory GHSA-7wx4-6vff-v64p lists affected ranges: PyPI diffusers >=0 <0.38.0)

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