diff --git a/.github/workflows/django.yml b/.github/workflows/django.yml
index 840a21a4..3409bcf6 100644
--- a/.github/workflows/django.yml
+++ b/.github/workflows/django.yml
@@ -6,6 +6,9 @@ on:
   pull_request:
     branches: ["main", "master"]
 
+permissions:
+  contents: read
+
 jobs:
   build:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/django_ci.yml b/.github/workflows/django_ci.yml
index 9311d263..96514403 100644
--- a/.github/workflows/django_ci.yml
+++ b/.github/workflows/django_ci.yml
@@ -10,6 +10,9 @@ on:
     paths:
       - 'backend/**'
 
+permissions:
+  contents: read
+
 jobs:
   build:
     runs-on: ubuntu-latest
diff --git a/backend/problems/serializers.py b/backend/problems/serializers.py
index bd973096..d3475f52 100644
--- a/backend/problems/serializers.py
+++ b/backend/problems/serializers.py
@@ -1,4 +1,3 @@
-from django.conf import settings
 from django.contrib.auth import get_user_model # Import get_user_model
 from rest_framework import serializers
 from .models import Tag, Problem, TestCase
diff --git a/backend/problems/tests.py b/backend/problems/tests.py
index 7ce503c2..49290204 100644
--- a/backend/problems/tests.py
+++ b/backend/problems/tests.py
@@ -1,3 +1,2 @@
-from django.test import TestCase
 
 # Create your tests here.
diff --git a/backend/problems/views.py b/backend/problems/views.py
index ccbc8fa7..92423b12 100644
--- a/backend/problems/views.py
+++ b/backend/problems/views.py
@@ -5,7 +5,7 @@
 from .models import Tag, Problem, TestCase
 from .serializers import TagSerializer, ProblemSerializer, ProblemDetailSerializer, TestCaseSerializer
 from users.models import User
-from users.permissions import IsAdminUser, IsProblemCreator, IsProblemVerifier, ProblemObjectPermissions
+from users.permissions import IsProblemCreator, IsProblemVerifier, ProblemObjectPermissions
 
 
 class TagViewSet(viewsets.ModelViewSet):
diff --git a/backend/submissions/judge_utils/comparison.py b/backend/submissions/judge_utils/comparison.py
index 3b05cdb2..951c245a 100644
--- a/backend/submissions/judge_utils/comparison.py
+++ b/backend/submissions/judge_utils/comparison.py
@@ -1,4 +1,3 @@
-import pathlib # Not strictly needed by this function but good for consistency if other utils use it
 from problems.models import Problem # For Problem.ComparisonMode
 
 def compare_outputs(
diff --git a/backend/submissions/judge_utils/execution.py b/backend/submissions/judge_utils/execution.py
index a825d3e2..e0a5ca39 100644
--- a/backend/submissions/judge_utils/execution.py
+++ b/backend/submissions/judge_utils/execution.py
@@ -1,6 +1,5 @@
 import pathlib
 import subprocess
-import random 
 from django.conf import settings # Import Django settings
 from ..models import Submission 
 
diff --git a/backend/submissions/serializers.py b/backend/submissions/serializers.py
index 9b49fac8..3a34a1cc 100644
--- a/backend/submissions/serializers.py
+++ b/backend/submissions/serializers.py
@@ -1,7 +1,7 @@
 from rest_framework import serializers
 from .models import Submission, SubmissionTestResult # Import SubmissionTestResult
 from users.serializers import UserSerializer 
-from problems.models import Problem, TestCase # Import TestCase for SubmissionTestResultSerializer
+from problems.models import Problem # Import TestCase for SubmissionTestResultSerializer
 
 class SubmissionTestResultSerializer(serializers.ModelSerializer):
     # test_case_id = serializers.ReadOnlyField(source='test_case.id') # Simple ID
diff --git a/backend/submissions/tasks.py b/backend/submissions/tasks.py
index 73fe1a29..3620161c 100644
--- a/backend/submissions/tasks.py
+++ b/backend/submissions/tasks.py
@@ -2,12 +2,8 @@
 from django.db import transaction
 from .models import Submission, SubmissionTestResult # Import SubmissionTestResult
 from problems.models import Problem, TestCase
-import time
-import random
-import subprocess
 import tempfile
 import pathlib
-import shutil
 
 from .judge_utils.comparison import compare_outputs
 from .judge_utils.compilation import compile_code_in_sandbox
diff --git a/backend/submissions/tests.py b/backend/submissions/tests.py
index 7ce503c2..49290204 100644
--- a/backend/submissions/tests.py
+++ b/backend/submissions/tests.py
@@ -1,3 +1,2 @@
-from django.test import TestCase
 
 # Create your tests here.
diff --git a/backend/users/adapters.py b/backend/users/adapters.py
index 683b7dbf..eb3f733a 100644
--- a/backend/users/adapters.py
+++ b/backend/users/adapters.py
@@ -1,7 +1,6 @@
 from allauth.account.adapter import DefaultAccountAdapter
 from allauth.socialaccount.adapter import DefaultSocialAccountAdapter
 from django.http import HttpResponseRedirect
-from django.urls import reverse
 
 class CustomAccountAdapter(DefaultAccountAdapter):
     def get_login_redirect_url(self, request):
diff --git a/backend/users/urls.py b/backend/users/urls.py
index b2c2d5eb..210a0876 100644
--- a/backend/users/urls.py
+++ b/backend/users/urls.py
@@ -1,6 +1,6 @@
 from django.urls import path, include
 from rest_framework.routers import DefaultRouter
-from .views import UserRegistrationView, PasswordChangeView, UserMeView, AdminUserViewSet, GoogleLogin, GithubLogin, AdminStatsView, UserViewSet
+from .views import UserRegistrationView, PasswordChangeView, UserMeView, AdminUserViewSet, AdminStatsView, UserViewSet
 
 app_name = "users"
 
diff --git a/backend/users/views.py b/backend/users/views.py
index dfb03800..c9ae1dd7 100644
--- a/backend/users/views.py
+++ b/backend/users/views.py
@@ -40,7 +40,6 @@ class PasswordChangeView(generics.GenericAPIView):
     permission_classes = [permissions.IsAuthenticated]
 
     def post(self, request, *args, **kwargs):
-        user = request.user
         serializer = self.get_serializer(data=request.data, context={'request': request})
         if serializer.is_valid(raise_exception=True):
             serializer.save()