diff --git a/CHANGES/3639.bugfix b/CHANGES/3639.bugfix
new file mode 100644
index 000000000..8ca6e6431
--- /dev/null
+++ b/CHANGES/3639.bugfix
@@ -0,0 +1 @@
+Fixed openapi schema generation by monkeypatching that drf JSONField is always an OA 'object'.
diff --git a/pulp_rpm/app/__init__.py b/pulp_rpm/app/__init__.py
index 3324c37e3..e035a6f66 100644
--- a/pulp_rpm/app/__init__.py
+++ b/pulp_rpm/app/__init__.py
@@ -11,3 +11,9 @@ class PulpRpmPluginAppConfig(PulpPluginAppConfig):
     version = "3.28.0.dev"
     python_package_name = "pulp-rpm"
     domain_compatible = True
+
+    def ready(self):
+        # include drf-spectacular Extension module
+        import pulp_rpm.app.schema.extensions  # noqa: E402, F401
+
+        super().ready()
diff --git a/pulp_rpm/app/schema/extensions.py b/pulp_rpm/app/schema/extensions.py
new file mode 100644
index 000000000..4c7634133
--- /dev/null
+++ b/pulp_rpm/app/schema/extensions.py
@@ -0,0 +1,23 @@
+"""drf-spectacular Extensions.
+
+See:
+https://drf-spectacular.readthedocs.io/en/latest/customization.html#step-5-extensions
+"""
+from drf_spectacular.extensions import OpenApiSerializerFieldExtension
+from drf_spectacular.plumbing import build_basic_type
+from drf_spectacular.types import OpenApiTypes
+
+
+class RestrictedJsonFieldExtension(OpenApiSerializerFieldExtension):
+    """
+    Workaround to makes drf JSONField to produce only Object Type.
+
+    See:
+    https://github.com/tfranzel/drf-spectacular/issues/1242
+    """
+
+    target_class = "rest_framework.fields.JSONField"
+    # match_subclasses = True  # not needed here but good to know.
+
+    def map_serializer_field(self, auto_schema, direction):
+        return build_basic_type(OpenApiTypes.OBJECT)