system: You are an expert security code reviewer. You will be shown a source code file along with a multi-select question listing several CWE (Common Weakness Enumeration) categories. Your task is to identify which of the listed CWEs are present in the code.

OUTPUT FORMAT: Respond with the letter(s) of all correct options, sorted alphabetically and comma-separated, wrapped in a single \boxed{...}. Examples: `\boxed{A}` for one correct, `\boxed{A,C}` for two, `\boxed{A,C,E}` for three. Output the boxed answer ONLY -- no explanation, no other text.

user: ```python
import json
import os

from django.contrib.auth.forms import UserCreationForm, PasswordResetForm
from django.core.exceptions import ValidationError
from django.core.validators import validate_email
from rest_framework.views import APIView
from rest_framework.response import Response
from django.contrib.auth import authenticate, login, logout
from django.contrib.auth.models import User

from auth_API.helpers import get_user_information, get_or_create_user_information
from daphne_API.daphne_fields import daphne_fields
from daphne_API.models import UserInformation


class Login(APIView):
    """
    Login a user
    """

    def post(self, request, format=None):
        # Try to authorize the user
        username = request.data['username']
        password = request.data['password']
        user = authenticate(request, username=username, password=password)

        if user is not None:
            # Try to look for user session object. If it exists, then the session will be changed to that. If not,
            # the current session information will be transferred to the user
            userinfo_qs = UserInformation.objects.filter(user__exact=user)

            if len(userinfo_qs) == 0:
                # Try to get or create a session user_info from the session and transfer it to the user
                userinfo = get_or_create_user_information(request.session, user)
                userinfo.user = user
                userinfo.session = None
                userinfo.save()

            # Log the user in
            login(request, user)

            # Return the login response
            return Response({
                'status': 'logged_in',
                'username': username,
                'permissions': []
            })
        else:
            # TODO: Get different messages based on auth error
            return Response({
                'status': 'auth_error',
                'login_error': 'This combination of username and password is not valid!'
            })


class Logout(APIView):
    """
    Logout a user -> Important!! When the frontend logs out it needs to start fresh
    """
    def post(self, request, format=None):
        # Log the user out
        logout(request)
        # Return the logout response
        return Response({
            'message': 'User logged out.'
        })


class Register(APIView):
    """
    Register a user
    """
    def post(self, request, format=None):
        username = request.data["username"]
        email = request.data["email"]
        password1 = request.data["password1"]
        password2 = request.data["password2"]

        # Validate all fields against our rules
        if not password1 or not password2 or password1 != password2:
            return Response({
                'status': 'registration_error',
                'registration_error': 'The passwords do not match.'
            })

        try:
            validate_email(email)
        except ValidationError:
            return Response({
                'status': 'registration_error',
                'registration_error': 'Email has an incorrect format.'
            })

        if username in ["default"]:
            return Response({
                'status': 'registration_error',
                'registration_error': 'This username is already in use.'
            })

        if User.objects.filter(username=username).exists():
            return Response({
                'status': 'registration_error',
                'registration_error': 'This username is already in use.'
            })

        # Do the registration procedure which includes creating folders for all problems
        try:
            user = User.objects.create_user(username, email, password1)
            user.save()
            # Create folders in the server structure
            os.mkdir('./daphne_API/data/' + username)
            problem_list = ["ClimateCentric", "Decadal2017Aerosols", "SMAP", "SMAP_JPL1", "SMAP_JPL2"]
            for problem in problem_list:
                os.mkdir('./daphne_API/data/' + username + '/' + problem)
        except ValueError:
            return Response({
                'status': 'registration_error',
                'registration_error': 'Please write a username.'
            })

        return Response({
            'status': 'registered'
        })


class ResetPassword(APIView):
    """
    Send a reset password email
    """
    def post(self, request, format=None):
        password_reset_form = PasswordResetForm(request.POST)
        if password_reset_form.is_valid():
            password_reset_form.save(request=request)

            return Response({
                'status': 'email sent'
            })
        else:
            return Response({
                'status': 'bad email'
            })


class CheckStatus(APIView):
    """
    Check if a user is logged in
    """
    def get(self, request, format=None):

        user_info = get_or_create_user_information(request.session, request.user, 'EOSS')

        problem = user_info.eosscontext.problem
        dataset_filename = user_info.eosscontext.dataset_name
        dataset_user = user_info.eosscontext.dataset_user

        response = {
            'username': request.user.username,
            'permissions': [],
            'problem': problem,
            'dataset_filename': dataset_filename,
            'dataset_user': dataset_user
        }

        if request.user.is_authenticated:
            response['is_logged_in'] = True
            # Transform the database design data into a json for the frontend
            response['data'] = []
            if len(user_info.eosscontext.design_set.all()) > 0:
                for design in user_info.eosscontext.design_set.all():
                    response['data'].append(
                        {'id': design.id, 'inputs': json.loads(design.inputs), 'outputs': json.loads(design.outputs)})
                response['modified_dataset'] = True
            else:
                response['modified_dataset'] = False
        else:
            response['is_logged_in'] = False
        return Response(response)

```

Which of the following CWE vulnerability categories are present in this code? Multiple options may be correct.

  A) CWE-116: Improper Encoding or Escaping of Output
  B) CWE-502: Deserialization of Untrusted Data
  C) CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
  D) CWE-215: Insertion of Sensitive Information Into Debugging Code
  E) CWE-730: OWASP Top Ten 2004 Category A9 - Denial of Service
  F) CWE-611: Improper Restriction of XML External Entity Reference
Answer: C