diff --git a/src/wp-includes/class-wp-meta-query.php b/src/wp-includes/class-wp-meta-query.php
index 5a1b0c4147..d6d65772fc 100644
--- a/src/wp-includes/class-wp-meta-query.php
+++ b/src/wp-includes/class-wp-meta-query.php
@@ -812,7 +812,7 @@ class WP_Meta_Query {
 			$clause_compare  = strtoupper( $clause['compare'] );
 			$sibling_compare = strtoupper( $sibling['compare'] );
 			if ( in_array( $clause_compare, $compatible_compares, true ) && in_array( $sibling_compare, $compatible_compares, true ) ) {
-				$alias = $sibling['alias'];
+				$alias = preg_replace( '/\W/', '_', $sibling['alias'] );
 				break;
 			}
 		}
diff --git a/src/wp-includes/class-wp-tax-query.php b/src/wp-includes/class-wp-tax-query.php
index 795309b498..a026bb1852 100644
--- a/src/wp-includes/class-wp-tax-query.php
+++ b/src/wp-includes/class-wp-tax-query.php
@@ -527,7 +527,7 @@ class WP_Tax_Query {
 
 			// The sibling must both have compatible operator to share its alias.
 			if ( in_array( strtoupper( $sibling['operator'] ), $compatible_operators, true ) ) {
-				$alias = $sibling['alias'];
+				$alias = preg_replace( '/\W/', '_', $sibling['alias'] );
 				break;
 			}
 		}