# CVE-2026-127208: datamodel-code-generator < 0.84.0 Code Injection via x-python-type Annotation

Status: published. Published: 2026-11-12. Updated: 2026-11-12.

datamodel-code-generator before 0.84.0 contains a code injection vulnerability that allows attackers to achieve arbitrary code execution by supplying a malicious JSON Schema with a crafted x-python-type annotation containing a string ast.Constant node in a subscript slice position, which bypasses validation in parse_python_type_annotation and _python_type_expr_from_ast. Attackers can embed malicious Python expressions such as __import__ calls within quoted string literals in the generated source code, which Pydantic v2 evaluates as a ForwardRef via eval() during model_rebuild(), resulting in arbitrary code execution on developer workstations, CI/CD pipelines, or applications that generate and import the produced models at runtime.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/datamodel-code-generator/datamodel-code-generator/commit/ebfc11d0644d37a71374b28aac06d98748e584ec

## Affected products and versions

- datamodel-code-generator / datamodel-code-generator (datamodel-code-generator): ≥ 0; < 0.84.0 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.6 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 8.8 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-94

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/datamodel-code-generator/datamodel-code-generator/releases/tag/0.84.0 (CNA: VulnCheck; release-notes)

- https://github.com/datamodel-code-generator/datamodel-code-generator/commit/ebfc11d0644d37a71374b28aac06d98748e584ec (CNA: VulnCheck; patch, issue-tracking)

- https://www.vulncheck.com/advisories/datamodel-code-generator-code-injection-via-x-python-type-annotation (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-127208; retrieved 2026-11-12; source updated 2026-11-12

Revision: 07c1aa562a494e70eeecbdad6b4c258a46007cb3dab9ae38308c47584ba65547

Canonical: https://y2.dev/cve/CVE-2026-127208

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