diff --git a/src/wp-includes/rest-api.php b/src/wp-includes/rest-api.php
index 5add20bc60..bdfd8fac42 100644
--- a/src/wp-includes/rest-api.php
+++ b/src/wp-includes/rest-api.php
@@ -1250,6 +1250,10 @@ function rest_validate_value_from_schema( $value, $args, $param = '' ) {
 	}
 
 	if ( 'object' === $args['type'] ) {
+		if ( '' === $value ) {
+			$value = array();
+		}
+
 		if ( $value instanceof stdClass ) {
 			$value = (array) $value;
 		}
diff --git a/tests/phpunit/tests/rest-api/rest-schema-sanitization.php b/tests/phpunit/tests/rest-api/rest-schema-sanitization.php
index 1b2fd1d90c..fc100f7b2b 100644
--- a/tests/phpunit/tests/rest-api/rest-schema-sanitization.php
+++ b/tests/phpunit/tests/rest-api/rest-schema-sanitization.php
@@ -275,6 +275,13 @@ class WP_Test_REST_Schema_Sanitization extends WP_UnitTestCase {
 		$this->assertEquals( array( 'a' => 1 ), rest_sanitize_value_from_schema( (object) array( 'a' => '1' ), $schema ) );
 	}
 
+	/**
+	 * @ticket 42961
+	 */
+	public function test_type_object_accepts_empty_string() {
+		$this->assertEquals( array(), rest_sanitize_value_from_schema( '', array( 'type' => 'object' ) ) );
+	}
+
 	public function test_type_unknown() {
 		$schema = array(
 			'type' => 'lalala',
diff --git a/tests/phpunit/tests/rest-api/rest-schema-validation.php b/tests/phpunit/tests/rest-api/rest-schema-validation.php
index 9c18a846dc..a6722d42a7 100644
--- a/tests/phpunit/tests/rest-api/rest-schema-validation.php
+++ b/tests/phpunit/tests/rest-api/rest-schema-validation.php
@@ -288,6 +288,13 @@ class WP_Test_REST_Schema_Validation extends WP_UnitTestCase {
 		$this->assertTrue( rest_validate_value_from_schema( (object) array( 'a' => 1 ), $schema ) );
 	}
 
+	/**
+	 * @ticket 42961
+	 */
+	public function test_type_object_allows_empty_string() {
+		$this->assertTrue( rest_validate_value_from_schema( '', array( 'type' => 'object' ) ) );
+	}
+
 	public function test_type_unknown() {
 		$schema = array(
 			'type' => 'lalala',