diff --git a/fastapi/datastructures.py b/fastapi/datastructures.py
index c04b5f0f3..479e1a7c3 100644
--- a/fastapi/datastructures.py
+++ b/fastapi/datastructures.py
@@ -139,7 +139,7 @@ class UploadFile(StarletteUploadFile):
     def __get_pydantic_json_schema__(
         cls, core_schema: Mapping[str, Any], handler: GetJsonSchemaHandler
     ) -> dict[str, Any]:
-        return {"type": "string", "format": "binary"}
+        return {"type": "string", "contentMediaType": "application/octet-stream"}
 
     @classmethod
     def __get_pydantic_core_schema__(