Fixes #5035: Fix exception when modifying an IP address assigned to a VM

docs/release-notes/version-2.9.md

@@ -4,6 +4,7 @@
 
 ### Bug Fixes
 
+* [#5035](https://github.com/netbox-community/netbox/issues/5035) - Fix exception when modifying an IP address assigned to a VM
 * [#5038](https://github.com/netbox-community/netbox/issues/5038) - Fix validation of primary IPs assigned to virtual machines
 
 ---

netbox/ipam/models.py

@@ -745,7 +745,7 @@ class IPAddress(ChangeLoggedModel, CustomFieldModel):
                         'vminterface': f"IP address is primary for virtual machine {vm} but not assigned to an "
                                        f"interface"
                     })
-                elif self.interface.virtual_machine != vm:
+                elif self.assigned_object.virtual_machine != vm:
                     raise ValidationError({
                         'vminterface': f"IP address is primary for virtual machine {vm} but assigned to "
                                        f"{self.assigned_object.virtual_machine} ({self.assigned_object})"