diff --git a/validator/client/validation_client.go b/validator/client/validation_client.go
index f436f0ba14..fa6b9000f2 100644
--- a/validator/client/validation_client.go
+++ b/validator/client/validation_client.go
@@ -158,7 +158,11 @@ func (c *ExecutionClient) LatestWasmModuleRoot() containers.PromiseInterface[com
 
 func (c *ExecutionClient) WriteToFile(input *validator.ValidationInput, expOut validator.GoGlobalState, moduleRoot common.Hash) containers.PromiseInterface[struct{}] {
 	jsonInput := server_api.ValidationInputToJson(input)
-	jsonInput.WriteToFile()
+	if err := jsonInput.WriteToFile(); err != nil {
+		return stopwaiter.LaunchPromiseThread[struct{}](c, func(ctx context.Context) (struct{}, error) {
+			return struct{}{}, err
+		})
+	}
 	return stopwaiter.LaunchPromiseThread[struct{}](c, func(ctx context.Context) (struct{}, error) {
 		err := c.client.CallContext(ctx, nil, server_api.Namespace+"_writeToFile", jsonInput, expOut, moduleRoot)
 		return struct{}{}, err
diff --git a/validator/server_api/json.go b/validator/server_api/json.go
index 3cec92418f..3dd817d5ae 100644
--- a/validator/server_api/json.go
+++ b/validator/server_api/json.go
@@ -71,7 +71,7 @@ func (i *InputJSON) WriteToFile() error {
 	if err != nil {
 		return err
 	}
-	if err = os.WriteFile(fmt.Sprintf("block_inputs_%d.json", i.Id), contents, 0644); err != nil {
+	if err = os.WriteFile(fmt.Sprintf("block_inputs_%d.json", i.Id), contents, 0600); err != nil {
 		return err
 	}
 	return nil