HuggingFace transformers vulnerable to remote code execution

Exploitation

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

CVSS

7.8 · CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

• CVE-2026-4372: 0.70% estimated exploitation activity in the next 30 days; percentile 53.07 (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.

A critical remote code execution vulnerability exists in all versions of the HuggingFace transformers library prior to version 5.3.0. The vulnerability allows an attacker to craft a malicious config.json file containing the attnimplementationinternal field set to an attacker-controlled HuggingFace Hub repository ID. When a victim loads this model using the standard AutoModelForCausalLM.frompretrained() API, the library downloads and executes arbitrary Python code from the attacker's repository with the victim's full OS privileges. This issue arises due to unfiltered deserialization of configuration attributes, insufficient sanitization of internal fields, and unsandboxed execution of downloaded kernels. The vulnerability bypasses the trustremotecode security mechanism, is invisible to the victim, and exploits the standard documented usage pattern, making it particularly severe. Users are advised to upgrade to version 5.3.0 or later to mitigate this issue.

Published by the source

26 May 2026, 13:30 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 13:46 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-29pf-2h5f-8g72

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-29pf-2h5f-8g72

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# Patch Next advisory brief: CVE-2026-4372

Advisory: HuggingFace transformers vulnerable to remote code execution
IDs: CVE-2026-4372, GHSA-29pf-2h5f-8g72
Record: https://patchnext.com/advisories/cve-2026-4372 (revision 2, source checked 26 Oct 2026, 13:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: transformers 5.3.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI transformers: affected < 5.3.0; fixed in 5.3.0

## Suggested inspection (read-only)
- `python -m pip show transformers`: 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 transformers.
- 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-29pf-2h5f-8g72 (OSV record GHSA-29pf-2h5f-8g72 lists affected ranges: PyPI transformers >=0 <5.3.0 (fixed))
- Verified: https://github.com/advisories/GHSA-29pf-2h5f-8g72 (GitHub-reviewed advisory GHSA-29pf-2h5f-8g72 lists affected ranges: PyPI transformers >=0 <5.3.0)

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