diff --git a/configs/swarm/executor.wasm b/configs/swarm/executor.wasm
index 2c2ef10a723..7347700b693 100644
Binary files a/configs/swarm/executor.wasm and b/configs/swarm/executor.wasm differ
diff --git a/data_model/src/lib.rs b/data_model/src/lib.rs
index 2e42a5d6aab..a475a90b916 100644
--- a/data_model/src/lib.rs
+++ b/data_model/src/lib.rs
@@ -868,9 +868,7 @@ mod model {
     /// String containing serialized valid JSON.
     ///
     /// This string is guaranteed to be parsed as JSON.
-    #[derive(
-        Display, Default, Debug, Clone, Encode, Decode, Ord, PartialOrd, Eq, PartialEq, IntoSchema,
-    )]
+    #[derive(Display, Debug, Clone, Encode, Decode, Ord, PartialOrd, Eq, PartialEq, IntoSchema)]
     #[ffi_type(unsafe {robust})]
     #[repr(transparent)]
     #[display(fmt = "{}", "0")]
@@ -906,6 +904,13 @@ impl JsonString {
     }
 }
 
+impl Default for JsonString {
+    fn default() -> Self {
+        // NOTE: empty string isn't valid JSON
+        Self("null".to_string())
+    }
+}
+
 impl From<&serde_json::Value> for JsonString {
     fn from(value: &serde_json::Value) -> Self {
         Self(value.to_string())