datamodel-code-generator vulnerable to code execution on import via x-python-type JSON-Schema extension in datamodel-code-generator

Exploitation

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

CVSS

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

EPSS

• CVE-2026-54655: 0.21% estimated exploitation activity in the next 30 days; percentile 11.25 (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.

Summary datamodel-code-generator honours a custom x-python-type JSON-Schema extension that lets a schema author override the generated Python type for a field. The value is forwarded verbatim into the generated Python source as the field annotation, with a single sanitisation pass that is trivial to bypass. An attacker who controls a JSON Schema fed to datamodel-codegen can therefore embed an arbitrary Python statement in the generated module, which executes at class-definition time the moment the developer imports the file. No --extra-template-data and no special flags are required; the vulnerable code is reachable with default settings. Details Sink: src/datamodelcodegenerator/parser/jsonschema.py, getpythontypeoverride (lines 2055–2096, at tag 0.60.1 / commit a321547e): DataType.type flows unescaped into {{ field.typehint }} in every model template (model/template/pydanticv2/BaseModel.jinja2, model/template/dataclass.jinja2, model/template/TypedDictClass.jinja2,…

Published by the source

28 Jul 2026, 21:33 UTC

Last modified by the source

28 Jul 2026, 21:34 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-m34r-v34r-rf9q

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# Patch Next advisory brief: CVE-2026-54655

Advisory: `datamodel-code-generator` vulnerable to code execution on import via `x-python-type` JSON-Schema extension in datamodel-code-generator
IDs: CVE-2026-54655, GHSA-m34r-v34r-rf9q
Record: https://patchnext.com/advisories/cve-2026-54655 (revision 1, source checked 26 Oct 2026, 13:50 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: datamodel-code-generator 0.60.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI datamodel-code-generator: affected >= 0.51.0, <= 0.60.1; fixed in 0.60.2

## Suggested inspection (read-only)
- `python -m pip show datamodel-code-generator`: 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 datamodel-code-generator.
- 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://github.com/advisories/GHSA-m34r-v34r-rf9q (GitHub-reviewed advisory GHSA-m34r-v34r-rf9q lists affected ranges: PyPI datamodel-code-generator >=0.51.0 <=0.60.1)

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