Description

Detects open redirect vulnerabilities in Starlette applications where user-controlled input is passed directly to RedirectResponse without proper validation. This could allow attackers to redirect users to malicious websites by manipulating redirect URL parameters.

Detection Strategy

• Checks if starlette-related imports are present in the codebase

• Identifies imports of starlette.responses.RedirectResponse

• Locates calls to RedirectResponse where the URL argument contains user-controlled input from query parameters or request headers

• Verifies the URL parameter is not sanitized or validated before use

• Reports a vulnerability when unsafe user input flows into RedirectResponse without proper validation

Vulnerable code example

from starlette.applications import Starlette
from starlette.requests import Request
from starlette.responses import RedirectResponse
from starlette.routing import Route

app = Starlette(routes=[])

async def unsafe_redirect(request: Request):...

✅ Secure code example

from starlette.applications import Starlette
from starlette.requests import Request
from starlette.responses import RedirectResponse
from starlette.routing import Route
from urllib.parse import urlparse

app = Starlette(routes=[])
...