CVE-2026-55403: datamodel-code-generator Authorization / Request Headers Leaked Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-r5vv-ff45-prp2",
  "modified" : "2026-07-28T21:32:08Z",
  "published" : "2026-07-28T21:32:08Z",
  "aliases" : [ "CVE-2026-55403" ],
  "summary" : "datamodel-code-generator: Authorization / request headers leaked to cross-origin redirect target when fetching remote schemas",
  "details" : "### Summary\n\nWhen `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.\n\n### Details\n\nIn `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:\n\n```python\nfor redirect_count in range(MAX_HTTP_REDIRECTS + 1):\n    _validate_url_for_fetch(current_url, allow_private_network=allow_private_network)\n    response = httpx.get(current_url, headers=headers, follow_redirects=False, ...)  # same headers every hop\n    if (redirect_url := _get_redirect_url(httpx, current_url, response)) is None:\n        break\n    current_url = redirect_url\n```\n\nBrowsers 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.\n\n### PoC\n\nSelf-contained reproducer: https://gist.github.com/thegr1ffyn/ade3035d7f2be95e16f11698259cdbc2  \nHost 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. \n\n(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.)\n\n### Impact\n\nExposure 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.\n\n### Suggested remediation\n\nWhen a redirect changes the origin (scheme/host/port), drop `Authorization` and other sensitive headers before following it, matching the behavior of mainstream HTTP clients.\n\n### Maintainer status\n\nConfirmed 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\n\nFix summary: strip `Authorization`, `Cookie`, and `Proxy-Authorization` headers when a redirect crosses origin; preserve headers for same-origin redirects.\n\nRelease status: fixed in `0.63.0`; `0.62.0` and earlier are affected.\n\nValidation: `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.\n\nSubmitted by: Hamza Haroon (thegr1ffyn)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "datamodel-code-generator"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.63.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.62.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/koxudaxi/datamodel-code-generator/security/advisories/GHSA-r5vv-ff45-prp2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/koxudaxi/datamodel-code-generator/commit/a585c037c8307b7aae815de193b7fe1c4c44994b"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/koxudaxi/datamodel-code-generator"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/koxudaxi/datamodel-code-generator/releases/tag/0.63.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200", "CWE-601" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-28T21:32:08Z",
    "nvd_published_at" : null
  }
}