GHSA-rfr2-mq9m-x2qx: datamodel-code-generator vulnerable to SSRF via --url: no host/IP validation, follows redirects

Summary datamodel-code-generator's built-in HTTP fetcher (http.get_body) issues an httpx.GET against any URL passed to --url (or reached via a redirect chain) with **no allow-list, no deny-list, no IP/host validation, and follow_redirects=True**. Loopback addresses, RFC1918 ranges, link-local (169.254.169.254 cloud metadata), unique-local IPv6 and any other network-accessible target are all reachable. The JSON/YAML response body is parsed as a schema and reflected into the generated .py source, exfiltrating the response to anyone with access to that file (commonly committed to a repository). Details Sink: src/datamodel_code_generator/http.py, get_body (lines 31–61, at tag 0.60.1 / commit a321547e): def get_body(url, headers=None, ignore_tls=False, query_parameters=None, timeout=DEFAULT_HTTP_TIMEOUT) -> str: httpx = _get_httpx() try: response = httpx.get( url, headers=headers, verify=not ignore_tls, follow_redirects=True, # (A) params=query_parameters, timeout=timeout, ) except Exception as e: ... if response.status_code >= 400: ... content_type = response.headers.get("content-type", "").lower() if "text/html" in content_type: raise SchemaFetchError(...) # (B) — only filter return response.text # (C) → embedded in generated.py - (A) follows redirects unconditionally — a public URL → 302 → internal address chain works. - (B) the only filter is rejecting text/html. Non-HTML internal endpoints (JSON APIs, cloud metadata, admin services) pass through. - (C) the response body becomes the schema; its title, description, properties, etc. land in the generated .py as class attributes and Field(description=...) strings. get_body is called by parser/base.py:1326 (_get_text_from_url), which is reached from CLI argument --url <URL>. (The $ref path is a separate advisory — see GHSA-D.) Only affects users who installed the [http] extra (pip install 'datamodel-code-generator[http]'). PoC A self-contained one-file PoC available here: https://gist.github.com/thegr1ffyn/18de7