diff --git a/wp-includes/taxonomy.php b/wp-includes/taxonomy.php
index 9865f42be7..78dd52ced9 100644
--- a/wp-includes/taxonomy.php
+++ b/wp-includes/taxonomy.php
@@ -2579,8 +2579,13 @@ function wp_insert_term( $term, $taxonomy, $args = array() ) {
 	if ( $args['parent'] > 0 && ! term_exists( (int) $args['parent'] ) ) {
 		return new WP_Error( 'missing_parent', __( 'Parent term does not exist.' ) );
 	}
+
 	$args['name'] = $term;
 	$args['taxonomy'] = $taxonomy;
+
+	// Coerce null description to strings, to avoid database errors.
+	$args['description'] = (string) $args['description'];
+
 	$args = sanitize_term($args, $taxonomy, 'db');
 
 	// expected_slashed ($name)
diff --git a/wp-includes/version.php b/wp-includes/version.php
index cc0ab9dc7f..37b6a01d09 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.5-alpha-36205';
+$wp_version = '4.5-alpha-36214';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.