diff --git a/src/schemas/validation/meta.yaml b/src/schemas/validation/meta.yaml
index 52f5ea2ed0..0472fd5b27 100644
--- a/src/schemas/validation/meta.yaml
+++ b/src/schemas/validation/meta.yaml
@@ -29,6 +29,8 @@ $defs:
         additionalProperties:
           type: string
         type: object
+      defaultMapping:
+        type: string
       propertyName:
         type: string
     required:
diff --git a/tests/schema/pass/mega.yaml b/tests/schema/pass/mega.yaml
index 3e57fb9144..8304fbe199 100644
--- a/tests/schema/pass/mega.yaml
+++ b/tests/schema/pass/mega.yaml
@@ -55,6 +55,7 @@ components:
                   propertyName: type
                   mapping:
                     foo: Foo
+                  defaultMapping: Bar
                   x-extension: true
                 anyOf:
                 - $ref: "#/components/schemas/Foo"