diff --git a/netbox/dcim/api/serializers_/devicetypes.py b/netbox/dcim/api/serializers_/devicetypes.py
index 0bd8ba824..a5830fa90 100644
--- a/netbox/dcim/api/serializers_/devicetypes.py
+++ b/netbox/dcim/api/serializers_/devicetypes.py
@@ -1,3 +1,5 @@
+import decimal
+
 from django.utils.translation import gettext as _
 from rest_framework import serializers
 
@@ -22,7 +24,7 @@ class DeviceTypeSerializer(NetBoxModelSerializer):
         max_digits=4,
         decimal_places=1,
         label=_('Position (U)'),
-        min_value=0,
+        min_value=decimal.Decimal(0),
         default=1.0
     )
     subdevice_role = ChoiceField(choices=SubdeviceRoleChoices, allow_blank=True, required=False, allow_null=True)
diff --git a/netbox/netbox/api/serializers/base.py b/netbox/netbox/api/serializers/base.py
index 4445f62da..448d3dbb4 100644
--- a/netbox/netbox/api/serializers/base.py
+++ b/netbox/netbox/api/serializers/base.py
@@ -27,9 +27,13 @@ class BaseModelSerializer(serializers.ModelSerializer):
         self.nested = nested
         self._requested_fields = fields
 
+        # Disable validators for nested objects (which already exist)
+        if self.nested:
+            self.validators = []
+
         # If this serializer is nested but no fields have been specified,
         # default to using Meta.brief_fields (if set)
-        if nested and not fields:
+        if self.nested and not fields:
             self._requested_fields = getattr(self.Meta, 'brief_fields', None)
 
         super().__init__(*args, **kwargs)
diff --git a/netbox/virtualization/models/virtualmachines.py b/netbox/virtualization/models/virtualmachines.py
index 233d51d63..9d33ffeca 100644
--- a/netbox/virtualization/models/virtualmachines.py
+++ b/netbox/virtualization/models/virtualmachines.py
@@ -1,3 +1,5 @@
+import decimal
+
 from django.contrib.contenttypes.fields import GenericRelation
 from django.core.exceptions import ValidationError
 from django.core.validators import MinValueValidator
@@ -112,7 +114,7 @@ class VirtualMachine(ContactsMixin, RenderConfigMixin, ConfigContextModel, Prima
         null=True,
         verbose_name=_('vCPUs'),
         validators=(
-            MinValueValidator(0.01),
+            MinValueValidator(decimal.Decimal(0.01)),
         )
     )
     memory = models.PositiveIntegerField(
diff --git a/netbox/vpn/api/serializers_/tunnels.py b/netbox/vpn/api/serializers_/tunnels.py
index 3e131b1c1..b561f696a 100644
--- a/netbox/vpn/api/serializers_/tunnels.py
+++ b/netbox/vpn/api/serializers_/tunnels.py
@@ -47,7 +47,8 @@ class TunnelSerializer(NetBoxModelSerializer):
     group = TunnelGroupSerializer(
         nested=True,
         required=False,
-        allow_null=True
+        allow_null=True,
+        default=None
     )
     encapsulation = ChoiceField(
         choices=TunnelEncapsulationChoices
diff --git a/requirements.txt b/requirements.txt
index c042180ff..fe599e647 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -12,7 +12,7 @@ django-rq==2.10.2
 django-taggit==5.0.1
 django-tables2==2.7.0
 django-timezone-field==6.1.0
-djangorestframework==3.14.0
+djangorestframework==3.15.1
 drf-spectacular==0.27.1
 drf-spectacular-sidecar==2024.3.4
 feedparser==6.0.11