datamodel-code-generator vulnerable to code execution on import via unescaped validators entries in --extra-template-data

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-2026-54656: 0.25% estimated exploitation activity in the next 30 days; percentile 16.78 (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 When the Pydantic v2 output mode is in use, datamodel-code-generator reads a validators array from each model entry in the --extra-template-data file and synthesises a Pydantic @fieldvalidator(...) decorator from each entry. The field names and the validator mode are interpolated into the decorator call wrapped in unescaped single quotes. A value containing ' breaks out of the string literal, letting an attacker emit an arbitrary positional Python expression into the decorator. The expression is evaluated at class-definition time, i.e. the moment the developer imports the generated module. This is the same trust model as the recently-published GHSA-wjv6-jcfj-mf9r (extras-file comment injection) but the impact is full RCE rather than a docstring leak. Details Sink: src/datamodelcodegenerator/model/pydanticv2/basemodel.py, processvalidators (lines 405–449, at tag 0.60.1 / commit a321547e): The strings from (A) and (B) flow verbatim into…

Published by the source

28 Jul 2026, 21:44 UTC

Last modified by the source

28 Jul 2026, 21:44 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-8m8r-38jm-f355

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# Patch Next advisory brief: CVE-2026-54656

Advisory: `datamodel-code-generator` vulnerable to code execution on import via unescaped `validators` entries in --extra-template-data
IDs: CVE-2026-54656, GHSA-8m8r-38jm-f355
Record: https://patchnext.com/advisories/cve-2026-54656 (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 >= 0.52.1, <= 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-8m8r-38jm-f355 (GitHub-reviewed advisory GHSA-8m8r-38jm-f355 lists affected ranges: PyPI datamodel-code-generator >=0.52.1 <=0.60.1)

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