diff --git a/core/config/schema/core.data_types.schema.yml b/core/config/schema/core.data_types.schema.yml
index 65cc0dd7b8..cc12f30428 100644
--- a/core/config/schema/core.data_types.schema.yml
+++ b/core/config/schema/core.data_types.schema.yml
@@ -86,7 +86,9 @@ machine_name:
   type: string
   label: 'Machine name'
   constraints:
-    MachineName: {}
+    MachineName: {
+      replacePattern: '[^a-z0-9_]+'
+    }
 
 # PHP Date format string that is translatable.
 date_format:
diff --git a/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/MachineNameConstraintValidator.php b/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/MachineNameConstraintValidator.php
index d25f1da8f2..92314101ff 100644
--- a/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/MachineNameConstraintValidator.php
+++ b/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/MachineNameConstraintValidator.php
@@ -14,7 +14,7 @@ class MachineNameConstraintValidator extends ConstraintValidator {
    * {@inheritdoc}
    */
   public function validate($value, Constraint $constraint) {
-    if (!preg_match('/^[a-z0-9_]+$/', $value)) {
+    if (!preg_match($this->replacePattern, $value)) {
       $this->context->addViolation($constraint->message);
     }
   }