diff --git a/packages/core/src/models/jsonSchema4.ts b/packages/core/src/models/jsonSchema4.ts
index 21542403f..0904fcbb6 100644
--- a/packages/core/src/models/jsonSchema4.ts
+++ b/packages/core/src/models/jsonSchema4.ts
@@ -155,4 +155,5 @@ export interface JsonSchema4 {
 
   format?: string;
   const?: any;
+  [x: string]: unknown;
 }
diff --git a/packages/core/src/models/jsonSchema7.ts b/packages/core/src/models/jsonSchema7.ts
index c4a0243dc..122b29273 100644
--- a/packages/core/src/models/jsonSchema7.ts
+++ b/packages/core/src/models/jsonSchema7.ts
@@ -164,4 +164,5 @@ export interface JsonSchema7 {
   then?: JsonSchema7;
   else?: JsonSchema7;
   errorMessage?: any;
+  [x: string]: unknown;
 }