GHSA-wjv6-jcfj-mf9r is a high-severity (CVSS 7.8) Code Injection vulnerability in datamodel-code-generator. O3 Security confirms whether GHSA-wjv6-jcfj-mf9r is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
`datamodel-code-generator` vulnerable to code injection via unescaped carriage return in `--extra-template-data` `comment` field
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-wjv6-jcfj-mf9r plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 0 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
datamodel-code-generatorReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
datamodel-code-generator is vulnerable to code injection when a developer passes an --extra-template-data file whose comment value contains a literal \r (carriage return). The comment variable is rendered into a Python # comment in six built-in templates with no line-terminator escaping. Python's tokenizer treats a bare CR as a physical-line terminator (see Python language reference — Physical lines), so the comment ends at the \r and the text after it is parsed as Python, including, when the CR is followed by suitable indentation, as a statement within the class body that follows on the next template line.
Details
The vulnerable templates each contain # {{ comment }} with no escaping:
src/datamodel_code_generator/model/template/TypeAliasAnnotation.jinja2:12and:19src/datamodel_code_generator/model/template/TypeAliasType.jinja2:12and:19src/datamodel_code_generator/model/template/TypeStatement.jinja2:12and:19src/datamodel_code_generator/model/template/pydantic_v2/BaseModel.jinja2:4src/datamodel_code_generator/model/template/pydantic_v2/RootModel.jinja2:19src/datamodel_code_generator/model/template/pydantic_v2/RootModelTypeAlias.jinja2:13
The pydantic_v2/BaseModel.jinja2:4 site is representative:
class {{ class_name }}({{ base_class }}):{% if comment is defined %} # {{ comment }}{% endif %}
When the developer-supplied extras file populates comment for a model, the value reaches the template via DataModel.extra_template_data (set in src/datamodel_code_generator/model/base.py:736-742) and Jinja2 interpolates it raw. None of the templates use comment_safe, escape_docstring, or any other line-terminator filter.
PoC
Complete self contained POC is available at my secret gist: https://gist.github.com/thegr1ffyn/8ad6b8cb3cc2be9d3a0144aeb6896a3f
Impact
- Who's affected: any developer or CI pipeline that runs
datamodel-codegen --extra-template-data <file>where the extras file is influenced by attacker-controlled input. Realistic scenarios include:- Extras file generated from a third-party schema-annotation system.
- Extras file vendored from an upstream repository.
- Extras file produced by a script that merges multiple
commentsources. - Build pipelines that template the extras file from environment variables, ticket descriptions, or commit metadata.
- What it gains: arbitrary Python code execution in the importer's process at
importtime. - What it does NOT need: the schema itself can be entirely benign; only the extras file needs to contain the malicious
comment. - What does block it: not passing
--extra-template-data, or rejecting extras files whosecommentvalues contain\r,\x0b, or\x0cbefore invocation.
Resolution
The fix normalizes comment values from built-in --extra-template-data before template rendering. Inline comments now convert CRLF, bare CR, vertical tab, and form feed into LF and prefix continuation lines with # , so attacker-controlled text stays inside the generated Python comment block.
Remediation
Upgrade to datamodel-code-generator 0.60.2 or later.
This issue affects datamodel-code-generator versions >= 0.14.1, <= 0.60.1 and is fixed in 0.60.2.
Submitted by: Hamza Haroon (thegr1ffyn)
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | datamodel-code-generator | ≥ 0.14.1&&< 0.60.2 | 0.60.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for datamodel-code-generator. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update datamodel-code-generator to 0.60.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wjv6-jcfj-mf9r is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-wjv6-jcfj-mf9r is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-wjv6-jcfj-mf9r. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-wjv6-jcfj-mf9r in your dependencies?
O3 detects GHSA-wjv6-jcfj-mf9r across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.