GHSA-r5vv-ff45-prp2
datamodel-code-generator: Authorization / request headers leaked to cross-origin redirect target when fetching remote schemas
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| PyPI | datamodel-code-generator | < 0.63.0 | 0.63.0 |
Details
As written in the advisory (Markdown source, shown as plain text).
### Summary
When `datamodel-code-generator` fetches a remote schema and follows an HTTP redirect, it re-sends the original request headers, including any `Authorization` header, to the redirect target even when the redirect changes origin (host/port/scheme). Credentials that an operator scoped to a trusted schema host are therefore forwarded to an attacker-controlled or otherwise different host, leaking them.
### Details
In `src/datamodel_code_generator/http.py`, `get_body()` follows redirects manually and re-issues each hop with the same `headers` argument, with no check that the origin is unchanged:
```python
for redirect_count in range(MAX_HTTP_REDIRECTS + 1):
_validate_url_for_fetch(current_url, allow_private_network=allow_private_network)
response = httpx.get(current_url, headers=headers, follow_redirects=False, ...) # same headers every hop
if (redirect_url := _get_redirect_url(httpx, current_url, response)) is None:
break
current_url = redirect_url
```
Browsers and HTTP clients such as `requests`/`httpx` strip `Authorization` when a redirect crosses origin; here it is preserved unconditionally. Headers are operator-supplied via `--http-headers` (and credentials can also arrive through `--url` userinfo), so a redirect from the trusted host to any other host discloses them.
### PoC
Self-contained reproducer: https://gist.github.com/thegr1ffyn/ade3035d7f2be95e16f11698259cdbc2
Host A (the trusted schema host) 302-redirects to host B (a different origin) which records received headers; the request carries an auth token scoped to A.
(The PoC uses loopback servers; `allow_private_network=True` is only to avoid the separate SSRF guard blocking loopback and has no bearing on the leak.)
### Impact
Exposure of sensitive information to an unauthorized actor (CWE-200). Affects operators who pass authentication headers/credentials to fetch a remote schema (`--http-headers`, `--url` with userinfo) when the configured host issues a redirect to a different origin — e.g. a compromised or open-redirect-prone schema host, or a redirect chain influenced by an attacker-supplied `$ref`. The leaked credential can then be replayed against the trusted host. This is a credential-scoping weakness secondary to, and in the same component as, the project's other SSRF hardening.
### Suggested remediation
When a redirect changes the origin (scheme/host/port), drop `Authorization` and other sensitive headers before following it, matching the behavior of mainstream HTTP clients.
### Maintainer status
Confirmed by maintainer review and regression tests. The private fix PR was merged and released in `0.63.0`: https://github.com/koxudaxi/datamodel-code-generator-ghsa-r5vv-ff45-prp2/pull/1
Fix summary: strip `Authorization`, `Cookie`, and `Proxy-Authorization` headers when a redirect crosses origin; preserve headers for same-origin redirects.
Release status: fixed in `0.63.0`; `0.62.0` and earlier are affected.
Validation: `uv run --group test --extra http pytest tests/test_http.py` passed locally for the redirect regression coverage; `uv run --group fix ruff check src/datamodel_code_generator/http.py tests/test_http.py` passed.
Submitted by: Hamza Haroon (thegr1ffyn)
References
External links from the advisory. They lead to third-party sites.
- https://github.com/koxudaxi/datamodel-code-generator/security/advisories/GHSA-r5vv-ff45-prp2
- https://github.com/koxudaxi/datamodel-code-generator/commit/a585c037c8307b7aae815de193b7fe1c4c44994b
- https://github.com/koxudaxi/datamodel-code-generator
- https://github.com/koxudaxi/datamodel-code-generator/releases/tag/0.63.0