diff --git src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
index 25b7fa2d8c..ea628684b9 100644
--- src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
+++ src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
@@ -2243,6 +2243,11 @@ class WP_REST_Posts_Controller extends WP_REST_Controller {
 		$taxonomies = wp_list_filter( get_object_taxonomies( $this->post_type, 'objects' ), array( 'show_in_rest' => true ) );
 		foreach ( $taxonomies as $taxonomy ) {
 			$base                          = ! empty( $taxonomy->rest_base ) ? $taxonomy->rest_base : $taxonomy->name;
+
+			if ( array_key_exists( $base, $schema['properties'] ) ) {
+				_doing_it_wrong( __METHOD__, sprintf( __( "Property '%s' is already set on the schema." ), $base ), '5.4.0' );
+			}
+
 			$schema['properties'][ $base ] = array(
 				/* translators: %s: Taxonomy name. */
 				'description' => sprintf( __( 'The terms assigned to the object in the %s taxonomy.' ), $taxonomy->name ),
diff --git tests/phpunit/tests/rest-api/rest-posts-controller.php tests/phpunit/tests/rest-api/rest-posts-controller.php
index 2aca849347..869dbf6c49 100644
--- tests/phpunit/tests/rest-api/rest-posts-controller.php
+++ tests/phpunit/tests/rest-api/rest-posts-controller.php
@@ -3918,6 +3918,20 @@ class WP_Test_REST_Posts_Controller extends WP_Test_REST_Post_Type_Controller_Te
 		$this->assertArrayHasKey( 'categories', $properties );
 	}
 
+	/**
+	 * @ticket 48401
+	 */
+	public function test_get_item_schema_issues_doing_it_wrong_when_taxonomy_name_is_already_set_in_properties() {
+		$this->setExpectedIncorrectUsage( 'WP_REST_Posts_Controller::get_item_schema' );
+
+		// Register a taxonomy with 'status' as name.
+		register_taxonomy( 'status', 'post', array( 'show_in_rest' => true ) );
+
+		// Re-initialize the controller
+		$controller = new WP_REST_Posts_Controller( 'post' );
+		$controller->register_routes();
+	}
+
 	/**
 	 * @ticket 39805
 	 */