GHSA-8m8r-38jm-f355 is a high-severity (CVSS 7.8) Code Injection vulnerability in datamodel-code-generator. O3 Security confirms whether GHSA-8m8r-38jm-f355 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
`datamodel-code-generator` vulnerable to code execution on import via unescaped `validators` entries in --extra-template-data
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-8m8r-38jm-f355.
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-8m8r-38jm-f355 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 371,625 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
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 @field_validator(...) 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/datamodel_code_generator/model/pydantic_v2/base_model.py, _process_validators (lines 405–449, at tag 0.60.1 / commit a321547e):
def _process_validators(self) -> None:
validators = self.extra_template_data.get("validators")
if not validators:
return
...
for validator in validators:
fields = validator.get("fields") or [validator.get("field")]
fields = [f for f in fields if f]
if not fields:
continue
function_path: str = validator["function"]
function_name = function_path.rsplit(".", 1)[-1]
mode = validator.get("mode", "after")
fields_str = ", ".join(f"'{f}'" for f in fields) # (A) UNESCAPED
...
mode_str = f"mode='{mode}'" # (B) UNESCAPED
prepared_validators.append({
"fields_str": fields_str,
"mode_str": mode_str,
"method_name": method_name,
"function_name": function_name,
"mode": mode,
})
self._additional_imports.append(Import.from_full_path(function_path)) # (C)
The strings from (A) and (B) flow verbatim into src/datamodel_code_generator/model/template/pydantic_v2/BaseModel.jinja2:
@field_validator({{ v.fields_str }}, {{ v.mode_str }})
There is no repr() call, no identifier check, and no quote-escaping.
Secondary sink at (C): Import.from_full_path(function_path) splits on the last . and emits from <prefix> import <suffix>. A ; in function_path therefore lands in the generated import line and runs as a statement at module load.
PoC
A self-contained one-file PoC is available here: https://gist.github.com/thegr1ffyn/34d5c647e74487ffb2be27c76dace2aa
Impact
Arbitrary code execution in the developer's interpreter / CI runner the moment the generated module is imported. Anyone who accepts a --extra-template-data file from an untrusted source is impacted:
- Pull requests adding or modifying project-local
*.template-data.json/.codegen.jsonfiles consumed by amake codegenrule or pre-commit hook. - Configuration snippets pasted from issue templates, READMEs, or third-party guides.
- Multi-tenant CI systems where one tenant's config file is read by another tenant's build.
Same blast radius as GHSA-wjv6-jcfj-mf9r, but silent RCE rather than a docstring leak — significantly higher impact under the same threat model.
Introduced in 0.52.1 by commit
a2b27562(Add --validators option for Pydantic v2 field validators).
Resolution
The fix validates validators entries with Pydantic models before rendering them. Field names must be valid non-keyword Python identifiers, function must be a dotted Python identifier path, and mode must be one of Pydantic's supported validator modes. The generated decorator arguments now render field names with repr() and mode with !r, so validated values are still emitted as Python string literals.
Remediation
Upgrade to datamodel-code-generator 0.60.2 or later.
This issue affects datamodel-code-generator versions >= 0.52.1, <= 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 | ≥ 0.52.1&&< 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-8m8r-38jm-f355 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-8m8r-38jm-f355 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-8m8r-38jm-f355. 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-8m8r-38jm-f355 in your dependencies?
O3 detects GHSA-8m8r-38jm-f355 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.