### Description The URL validation of the homepage is less strict in FastAPI, allowing things like `https://aa...` with longer domain names than is valid and other such nonsense. None of this is particularly harmful except for some cases that cause `urlparse` from `urllib.parse` to throw a `ValueError` like unmatched `[]` that you see in IPv6 addresses. The `valid_homepage` function should catch these and return `False` disallowing them. ### Reproduction Try and set your Homepage URL on https://localhost:8444/account/uncoupling/edit to `https://[`. ### Logs ```py Traceback (most recent call last): File "/aurweb/./aurweb/asgi.py", line 197, in add_security_headers response = await util.error_or_result(call_next, request) File "/aurweb/./aurweb/util.py", line 228, in error_or_result response = await next(*args, **kwargs) File "/usr/lib/python3.10/site-packages/starlette/middleware/base.py", line 44, in call_next raise app_exc File "/usr/lib/python3.10/site-packages/starlette/middleware/base.py", line 34, in coro await self.app(scope, request.receive, send_stream.send) File "/usr/lib/python3.10/site-packages/starlette/middleware/base.py", line 63, in __call__ response = await self.dispatch_func(request, call_next) File "/usr/lib/python3.10/site-packages/prometheus_fastapi_instrumentator/instrumentation.py", line 172, in dispatch_middleware raise e from None File "/usr/lib/python3.10/site-packages/prometheus_fastapi_instrumentator/instrumentation.py", line 169, in dispatch_middleware response = await call_next(request) File "/usr/lib/python3.10/site-packages/starlette/middleware/base.py", line 44, in call_next raise app_exc File "/usr/lib/python3.10/site-packages/starlette/middleware/base.py", line 34, in coro await self.app(scope, request.receive, send_stream.send) File "/usr/lib/python3.10/site-packages/starlette/exceptions.py", line 82, in __call__ raise exc File "/usr/lib/python3.10/site-packages/starlette/exceptions.py", line 71, in __call__ await self.app(scope, receive, sender) File "/usr/lib/python3.10/site-packages/starlette/routing.py", line 656, in __call__ await route.handle(scope, receive, send) File "/usr/lib/python3.10/site-packages/starlette/routing.py", line 259, in handle await self.app(scope, receive, send) File "/usr/lib/python3.10/site-packages/starlette/routing.py", line 61, in app response = await func(request) File "/usr/lib/python3.10/site-packages/fastapi/routing.py", line 226, in app raw_response = await run_endpoint_function( File "/usr/lib/python3.10/site-packages/fastapi/routing.py", line 159, in run_endpoint_function return await dependant.call(**values) File "/aurweb/./aurweb/auth/__init__.py", line 181, in wrapper return await _auth_required(True)(func)(*args, **kwargs) File "/aurweb/./aurweb/auth/__init__.py", line 151, in wrapper return await func(request, *args, **kwargs) File "/aurweb/./aurweb/routers/accounts.py", line 402, in account_edit_post ok, errors = process_account_form(request, user, args) File "/aurweb/./aurweb/routers/accounts.py", line 150, in process_account_form check(**args, request=request, user=user, _=_) File "/aurweb/./aurweb/users/validate.py", line 98, in invalid_homepage if HP and not util.valid_homepage(HP): File "/aurweb/./aurweb/util.py", line 66, in valid_homepage parts = urlparse(homepage) File "/usr/lib/python3.10/urllib/parse.py", line 393, in urlparse splitresult = urlsplit(url, scheme, allow_fragments) File "/usr/lib/python3.10/urllib/parse.py", line 484, in urlsplit raise ValueError("Invalid IPv6 URL") ValueError: Invalid IPv6 URL ``` ### Version(s) FastAPI.