diff --git a/src/backend/InvenTree/InvenTree/permissions.py b/src/backend/InvenTree/InvenTree/permissions.py
index 060a698c83..807117c21d 100644
--- a/src/backend/InvenTree/InvenTree/permissions.py
+++ b/src/backend/InvenTree/InvenTree/permissions.py
@@ -486,6 +486,11 @@ class ContentTypePermission(OASTokenMixin, permissions.BasePermission):
 
     def has_object_permission(self, request, view, obj):
         """Check if the user has permission to access the object."""
+        permission = 'view' if request.method in permissions.SAFE_METHODS else 'change'
+
+        if hasattr(obj, 'check_permission'):
+            return obj.check_permission(permission, request.user)
+
         if model_class := obj.__class__:
             return users.permissions.check_user_permission(
                 request.user, model_class, 'change'
diff --git a/src/backend/InvenTree/common/api.py b/src/backend/InvenTree/common/api.py
index 22aae6d491..aeaf94af41 100644
--- a/src/backend/InvenTree/common/api.py
+++ b/src/backend/InvenTree/common/api.py
@@ -499,8 +499,37 @@ class NotesImageList(ListCreateAPI):
 
     filter_backends = SEARCH_ORDER_FILTER
 
+    def get_queryset(self):
+        """Filter notes images to those linked to a note the requesting user can view."""
+        import common.validators
+        from users.permissions import check_user_permission, prefetch_rule_sets
+
+        qs = super().get_queryset()
+        user = self.request.user
+
+        if user.is_superuser:
+            return qs
+
+        groups = prefetch_rule_sets(user)
+
+        allowed_ct_ids = [
+            ContentType.objects.get_for_model(model_class).pk
+            for model_class in common.validators.note_model_types()
+            if check_user_permission(user, model_class, 'view', groups=groups)
+        ]
+
+        return qs.filter(
+            Q(note__template=True) | Q(note__model_type__in=allowed_ct_ids)
+        )
+
     def perform_create(self, serializer):
         """Create (upload) a new notes image."""
+        note = serializer.validated_data['note']
+
+        common.serializers.check_note_change_permission(
+            self.request.user, template=note.template, model_type=note.model_type
+        )
+
         serializer.save(user=self.request.user)
 
 
@@ -1315,6 +1344,35 @@ class ParameterMixin:
     serializer_class = common.serializers.ParameterSerializer
     permission_classes = [IsAuthenticatedOrReadScope]
 
+    def get_queryset(self):
+        """Filter parameters to those the requesting user has view permission for.
+
+        Parameter has no RuleSet permissions of its own (see
+        users.ruleset.get_ruleset_ignore()) - access is instead scoped by the
+        'view' permission of the model type the parameter is linked to.
+        """
+        import common.validators
+        from users.permissions import check_user_permission, prefetch_rule_sets
+
+        qs = super().get_queryset()
+        user = self.request.user
+
+        if user.is_superuser:
+            return qs
+
+        # Fetch the user's groups (with prefetched rule sets) once, and reuse it
+        # for every model type below - otherwise each check_user_permission()
+        # call re-fetches the same groups/rule-sets from scratch.
+        groups = prefetch_rule_sets(user)
+
+        allowed_ct_ids = [
+            ContentType.objects.get_for_model(model_class).pk
+            for model_class in common.validators.parameter_model_types()
+            if check_user_permission(user, model_class, 'view', groups=groups)
+        ]
+
+        return qs.filter(model_type__in=allowed_ct_ids)
+
 
 class ParameterList(
     OutputOptionsMixin,
@@ -1346,10 +1404,44 @@ class ParameterList(
 
     unique_create_fields = ['model_type', 'model_id', 'template']
 
+    def validate_delete(self, queryset, request) -> None:
+        """Ensure that the user has correct permissions for a bulk-delete.
+
+        - Extract all model types from the provided queryset
+        - Ensure that the user has correct 'delete' permissions for each linked model
+        """
+        from users.permissions import check_user_permission
+
+        content_type_ids = queryset.values_list('model_type', flat=True).distinct()
+
+        for content_type in ContentType.objects.filter(pk__in=content_type_ids):
+            model_class = content_type.model_class()
+
+            if not model_class or not check_user_permission(
+                request.user, model_class, 'delete'
+            ):
+                raise ValidationError(
+                    _('User does not have permission to delete these parameters')
+                )
+
 
 class ParameterDetail(ParameterMixin, RetrieveUpdateDestroyAPI):
     """Detail API endpoint for Parameter objects."""
 
+    def perform_destroy(self, instance):
+        """Enforce a delete permission check on the linked model before deleting.
+
+        DRF's default destroy() calls instance.delete() directly, bypassing
+        ParameterSerializer.save() (and the permission checks it performs)
+        entirely. Without this, get_queryset()'s 'view' permission gate is
+        all that stands between a user and deleting the parameter.
+        """
+        if not instance.check_permission('delete', self.request.user):
+            raise PermissionDenied(
+                _('User does not have permission to delete this parameter')
+            )
+        super().perform_destroy(instance)
+
 
 class InstanceInfoView(APIView):
     """Return aggregated attachment/note/parameter counts for a single model instance.
diff --git a/src/backend/InvenTree/common/models.py b/src/backend/InvenTree/common/models.py
index 204adca8e2..0538e7c483 100644
--- a/src/backend/InvenTree/common/models.py
+++ b/src/backend/InvenTree/common/models.py
@@ -170,6 +170,10 @@ class ProjectCode(InvenTree.models.InvenTreeMetadataModel):
         """String representation of a ProjectCode."""
         return self.code
 
+    def check_permission(self, permission, user):
+        """Check if the user has the required permission for this project code."""
+        return permission == 'view' or user.is_staff
+
     code = models.CharField(
         max_length=50,
         unique=True,
@@ -3299,6 +3303,20 @@ class Note(
         self.check_delete()
         super().delete(*args, **kwargs)
 
+    def check_permission(self, permission, user):
+        """Check if the user has the required permission for this note."""
+        from InvenTree.models import InvenTreeNoteMixin
+
+        if self.template:
+            return user.is_staff
+
+        model_class = self.model_type.model_class() if self.model_type else None
+
+        if not model_class or not issubclass(model_class, InvenTreeNoteMixin):
+            return False
+
+        return model_class.check_related_permission(permission, user)
+
     def cleanup_images(self):
         """Remove any images which are no longer referenced in the note content."""
         for image in self.images.all():
diff --git a/src/backend/InvenTree/common/test_api.py b/src/backend/InvenTree/common/test_api.py
index 5000ff88ac..3c7d831992 100644
--- a/src/backend/InvenTree/common/test_api.py
+++ b/src/backend/InvenTree/common/test_api.py
@@ -595,6 +595,12 @@ class ParameterAPITests(InvenTreeAPITestCase):
         self.assertEqual(data['data'], '-2 inches')
         self.assertAlmostEqual(data['data_numeric'], -50.8, places=2)
 
+        # Deleting requires 'delete' permission against the linked model - the
+        # 'add' permission granted above is not sufficient
+        response = self.delete(url, expected_code=403)
+
+        self.assignRole('part.delete')
+
         # Finally, delete the Parameter via the API
         response = self.delete(url, expected_code=204)
 
@@ -2847,6 +2853,10 @@ class NotesImageAPITests(InvenTreeAPITestCase):
 
         super().setUp()
 
+        # 'change' also grants 'view' (see RuleSet.save()), covering both the
+        # upload permission check and the get_queryset() view-permission filter
+        self.assignRole('part.change')
+
         self.part = Part.objects.create(name='Notes Image Test Part', description='x')
         ct = ContentType.objects.get_for_model(Part)
         self.note = common.models.Note.objects.create(
@@ -2929,3 +2939,307 @@ class NotesImageAPITests(InvenTreeAPITestCase):
         buf = io.BytesIO()
         Image.new('RGB', (16, 16), color='red').save(buf, format='PNG')
         return buf.getvalue()
+
+
+class ParameterPermissionAPITests(InvenTreeAPITestCase):
+    """Tests for Parameter API permission enforcement."""
+
+    # No roles by default - each test assigns only what it needs
+    roles = []
+
+    def setUp(self):
+        """Create a Part, ParameterTemplate and pre-existing Parameter."""
+        from part.models import Part
+
+        super().setUp()
+
+        self.part = Part.objects.create(
+            name='Perm Test Part', description='Part for permission testing'
+        )
+
+        self.template = common.models.ParameterTemplate.objects.create(
+            name='Perm Test Template', model_type=self.part.get_content_type()
+        )
+
+        # Create a parameter directly via ORM (bypasses API permission checks)
+        self.parameter = common.models.Parameter.objects.create(
+            model_type=self.part.get_content_type(),
+            model_id=self.part.pk,
+            template=self.template,
+            data='1',
+        )
+
+    def _parameter_url(self, pk=None):
+        if pk:
+            return reverse('api-parameter-detail', kwargs={'pk': pk})
+        return reverse('api-parameter-list')
+
+    def test_list_parameters_no_role_returns_empty(self):
+        """A user with no roles cannot see parameters attached to a Part."""
+        response = self.get(
+            self._parameter_url(),
+            data={'model_type': 'part', 'model_id': self.part.pk},
+            expected_code=200,
+        )
+        self.assertEqual(len(response.data), 0)
+
+    def test_list_parameters_with_view_role_returns_parameters(self):
+        """A user with part.view can see parameters attached to a Part."""
+        self.assignRole('part.view')
+        response = self.get(
+            self._parameter_url(),
+            data={'model_type': 'part', 'model_id': self.part.pk},
+            expected_code=200,
+        )
+        pks = [p['pk'] for p in response.data]
+        self.assertIn(self.parameter.pk, pks)
+
+    def test_detail_parameter_no_role_returns_404(self):
+        """A user with no roles gets 404 for a parameter attached to a Part."""
+        self.get(self._parameter_url(self.parameter.pk), expected_code=404)
+
+    def test_delete_parameter_view_only_role_is_denied(self):
+        """A user with only 'view' permission must not be able to delete a parameter.
+
+        Regression test: ParameterDetail (RetrieveUpdateDestroyAPI) used DRF's
+        default destroy()/perform_destroy(), which calls instance.delete()
+        directly - bypassing any permission check entirely. A 'view'-only user
+        (visible via get_queryset(), but without 'delete') must not be able to
+        delete the parameter.
+        """
+        self.assignRole('part.view')
+        self.delete(self._parameter_url(self.parameter.pk), expected_code=403)
+        self.assertTrue(
+            common.models.Parameter.objects.filter(pk=self.parameter.pk).exists()
+        )
+
+    def test_delete_parameter_with_delete_role_is_allowed(self):
+        """A user with part.delete can delete a parameter for a Part."""
+        self.assignRole('part.delete')
+        self.delete(self._parameter_url(self.parameter.pk), expected_code=204)
+        self.assertFalse(
+            common.models.Parameter.objects.filter(pk=self.parameter.pk).exists()
+        )
+
+    def test_bulk_delete_parameter_view_only_role_is_denied(self):
+        """A user with only 'view' permission must not be able to bulk-delete parameters.
+
+        Regression test: ParameterList (BulkDeleteMixin) had no validate_delete()
+        override, so the bulk-delete endpoint bypassed permission checks entirely.
+        """
+        self.assignRole('part.view')
+        self.delete(
+            self._parameter_url(),
+            data={'items': [self.parameter.pk]},
+            expected_code=400,
+        )
+        self.assertTrue(
+            common.models.Parameter.objects.filter(pk=self.parameter.pk).exists()
+        )
+
+    def test_bulk_delete_parameter_with_delete_role_is_allowed(self):
+        """A user with part.delete can bulk-delete parameters for a Part."""
+        self.assignRole('part.delete')
+        self.delete(
+            self._parameter_url(),
+            data={'items': [self.parameter.pk]},
+            expected_code=200,
+        )
+        self.assertFalse(
+            common.models.Parameter.objects.filter(pk=self.parameter.pk).exists()
+        )
+
+
+class NotesImagePermissionAPITests(InvenTreeAPITestCase):
+    """Tests for NotesImage API permission enforcement.
+
+    Regression coverage for a permission gap: NotesImageList had no queryset
+    scoping and no permission check in perform_create(), so a user with no
+    (or insufficient) permission against the model a note was attached to
+    could still see, and attach images to, that note.
+    """
+
+    # No roles by default - each test assigns only what it needs
+    roles = []
+
+    def setUp(self):
+        """Create a Part and a pre-existing Note to attach images to."""
+        from django.contrib.contenttypes.models import ContentType
+
+        from part.models import Part
+
+        super().setUp()
+
+        self.part = Part.objects.create(
+            name='Perm Test Part', description='Part for permission testing'
+        )
+        ct = ContentType.objects.get_for_model(Part)
+        self.note = common.models.Note.objects.create(
+            model_type=ct, model_id=self.part.pk, title='N', content='<p>c</p>'
+        )
+        self.image = common.models.NotesImage.objects.create(note=self.note)
+        self.image.image.save('a.png', ContentFile(self._image_bytes()))
+
+    def _image_bytes(self):
+        buf = io.BytesIO()
+        Image.new('RGB', (16, 16), color='blue').save(buf, format='PNG')
+        return buf.getvalue()
+
+    def _generate_upload(self, name='test.png'):
+        buf = io.BytesIO()
+        Image.new('RGB', (16, 16), color='blue').save(buf, format='PNG')
+        buf.seek(0)
+        return SimpleUploadedFile(name, buf.read(), content_type='image/png')
+
+    def test_list_images_no_role_returns_empty(self):
+        """A user with no roles cannot see images attached to the note."""
+        response = self.get(reverse('api-notes-image-list'), expected_code=200)
+        pks = [i['pk'] for i in response.data]
+        self.assertNotIn(self.image.pk, pks)
+
+    def test_list_images_with_view_role_returns_images(self):
+        """A user with part.view can see images attached to the note."""
+        self.assignRole('part.view')
+        response = self.get(reverse('api-notes-image-list'), expected_code=200)
+        pks = [i['pk'] for i in response.data]
+        self.assertIn(self.image.pk, pks)
+
+    def test_upload_no_role_is_denied(self):
+        """A user with no roles cannot attach an image to the note."""
+        self.post(
+            reverse('api-notes-image-list'),
+            data={'image': self._generate_upload(), 'note': self.note.pk},
+            format='multipart',
+            expected_code=403,
+        )
+
+    def test_upload_view_only_role_is_denied(self):
+        """A user with only part.view cannot attach an image to the note.
+
+        'view' does not imply 'change' in the InvenTree ruleset hierarchy.
+        """
+        self.assignRole('part.view')
+        self.post(
+            reverse('api-notes-image-list'),
+            data={'image': self._generate_upload(), 'note': self.note.pk},
+            format='multipart',
+            expected_code=403,
+        )
+
+    def test_upload_with_change_role_is_allowed(self):
+        """A user with part.change can attach an image to the note."""
+        self.assignRole('part.change')
+        self.post(
+            reverse('api-notes-image-list'),
+            data={'image': self._generate_upload(), 'note': self.note.pk},
+            format='multipart',
+            expected_code=201,
+        )
+
+
+class GenericMetadataAuthorizationTests(InvenTreeAPITestCase):
+    """Tests for the generic '/api/metadata/<model>/pk/<pk>/' endpoint.
+
+    Regression coverage for a permission gap: several models (Attachment,
+    Parameter, Note, ProjectCode) have no RuleSet permissions of their own
+    (see users.ruleset.get_ruleset_ignore()) - access to them is meant to be
+    scoped by a different rule instead (typically the RuleSet permission of
+    another model they're linked to). ContentTypePermission previously
+    treated that ignore-listing as blanket permission-exemption for *any*
+    request against the object's own (ignore-listed) model, regardless of
+    what its dedicated endpoint enforces - so this generic, catch-all
+    metadata endpoint could read/write metadata on any Attachment/Parameter/
+    Note/ProjectCode, bypassing whatever permission its own endpoint required.
+    """
+
+    roles = []
+
+    def setUp(self):
+        """Create a Part plus one linked Attachment, Parameter and Note."""
+        from part.models import Part
+
+        super().setUp()
+
+        self.part = Part.objects.create(name='Metadata Perm Test Part', description='x')
+
+        self.attachment = common.models.Attachment.objects.create(
+            model_type='part', model_id=self.part.pk, link='https://example.com'
+        )
+
+        template = common.models.ParameterTemplate.objects.create(
+            name='Metadata Perm Test Template', model_type=self.part.get_content_type()
+        )
+        self.parameter = common.models.Parameter.objects.create(
+            model_type=self.part.get_content_type(),
+            model_id=self.part.pk,
+            template=template,
+            data='1',
+        )
+
+        self.note = common.models.Note.objects.create(
+            model_type=self.part.get_content_type(),
+            model_id=self.part.pk,
+            title='N',
+            content='<p>c</p>',
+        )
+
+        self.project_code = common.models.ProjectCode.objects.create(code='PERM-001')
+
+    def _metadata_url(self, model, pk):
+        return reverse('api-generic-metadata', kwargs={'model': model, 'pk': pk})
+
+    def test_attachment_metadata_requires_linked_permission(self):
+        """Attachment metadata is scoped by 'view'/'change' on the linked Part."""
+        url = self._metadata_url('attachment', self.attachment.pk)
+
+        self.get(url, expected_code=403)
+        self.patch(url, {'metadata': {'x': 1}}, expected_code=403)
+
+        self.assignRole('part.view')
+        self.get(url, expected_code=200)
+        self.patch(url, {'metadata': {'x': 1}}, expected_code=403)
+
+        self.assignRole('part.change')
+        self.patch(url, {'metadata': {'x': 1}}, expected_code=200)
+
+    def test_parameter_metadata_requires_linked_permission(self):
+        """Parameter metadata is scoped by 'view'/'change' on the linked Part."""
+        url = self._metadata_url('parameter', self.parameter.pk)
+
+        self.get(url, expected_code=403)
+        self.patch(url, {'metadata': {'x': 1}}, expected_code=403)
+
+        self.assignRole('part.view')
+        self.get(url, expected_code=200)
+        self.patch(url, {'metadata': {'x': 1}}, expected_code=403)
+
+        self.assignRole('part.change')
+        self.patch(url, {'metadata': {'x': 1}}, expected_code=200)
+
+    def test_note_metadata_requires_linked_permission(self):
+        """Note metadata is scoped by 'view'/'change' on the linked Part."""
+        url = self._metadata_url('note', self.note.pk)
+
+        self.get(url, expected_code=403)
+        self.patch(url, {'metadata': {'x': 1}}, expected_code=403)
+
+        self.assignRole('part.view')
+        self.get(url, expected_code=200)
+        self.patch(url, {'metadata': {'x': 1}}, expected_code=403)
+
+        self.assignRole('part.change')
+        self.patch(url, {'metadata': {'x': 1}}, expected_code=200)
+
+    def test_project_code_metadata_requires_staff_for_write(self):
+        """ProjectCode metadata mirrors the staff-only write restriction of its own endpoint."""
+        url = self._metadata_url('projectcode', self.project_code.pk)
+
+        # Reading metadata does not require staff (matches IsStaffOrReadOnlyScope)
+        self.user.is_staff = False
+        self.user.save()
+        self.get(url, expected_code=200)
+        self.patch(url, {'metadata': {'x': 1}}, expected_code=403)
+
+        self.user.is_staff = True
+        self.user.save()
+        self.patch(url, {'metadata': {'x': 1}}, expected_code=200)
diff --git a/src/backend/InvenTree/users/models.py b/src/backend/InvenTree/users/models.py
index 0e6e1eb316..a9f41f241a 100644
--- a/src/backend/InvenTree/users/models.py
+++ b/src/backend/InvenTree/users/models.py
@@ -496,6 +496,15 @@ class UserProfile(InvenTree.models.MetadataMixin):
     user = models.OneToOneField(
         User, on_delete=models.CASCADE, related_name='profile', verbose_name=_('User')
     )
+
+    def check_permission(self, permission, user):
+        """Check if the user has the required permission for this profile.
+
+        UserProfile has no RuleSet permissions of its own,
+        so we manually check if the user is the owner of this profile.
+        """
+        return self.user_id == user.pk
+
     language = models.CharField(
         max_length=10,
         blank=True,
diff --git a/src/backend/InvenTree/users/tests.py b/src/backend/InvenTree/users/tests.py
index a00fb671b2..490889a3e0 100644
--- a/src/backend/InvenTree/users/tests.py
+++ b/src/backend/InvenTree/users/tests.py
@@ -500,3 +500,34 @@ class UserProfileTest(InvenTreeAPITestCase):
         # Ensure primary_group is set to None
         profile.refresh_from_db()
         self.assertIsNone(profile.primary_group)
+
+
+class UserProfileMetadataPermissionTests(InvenTreeAPITestCase):
+    """Tests for the generic metadata endpoint against the UserProfile model."""
+
+    def setUp(self):
+        """Create a second user with their own profile."""
+        from django.contrib.auth import get_user_model
+
+        super().setUp()
+
+        self.other_user = get_user_model().objects.create_user(
+            username='other_metadata_user', password='password'
+        )
+
+    def _metadata_url(self, pk):
+        return reverse(
+            'api-generic-metadata', kwargs={'model': 'userprofile', 'pk': pk}
+        )
+
+    def test_own_profile_metadata_is_accessible(self):
+        """A user can read/write their own profile metadata via the generic endpoint."""
+        url = self._metadata_url(self.user.profile.pk)
+        self.get(url, expected_code=200)
+        self.patch(url, {'metadata': {'x': 1}}, expected_code=200)
+
+    def test_other_users_profile_metadata_is_denied(self):
+        """A user cannot read/write another user's profile metadata via the generic endpoint."""
+        url = self._metadata_url(self.other_user.profile.pk)
+        self.get(url, expected_code=403)
+        self.patch(url, {'metadata': {'x': 1}}, expected_code=403)