diff --git a/src/wp-includes/rest-api.php b/src/wp-includes/rest-api.php
index 988dd9c778..8642460dd8 100644
--- a/src/wp-includes/rest-api.php
+++ b/src/wp-includes/rest-api.php
@@ -1097,6 +1097,9 @@ function rest_sanitize_value_from_schema( $value, $args ) {
 		if ( empty( $args['items'] ) ) {
 			return (array) $value;
 		}
+		if ( ! is_array( $value ) ) {
+			$value = preg_split( '/[\s,]+/', $value );
+		}
 		foreach ( $value as $index => $v ) {
 			$value[ $index ] = rest_sanitize_value_from_schema( $v, $args['items'] );
 		}
diff --git a/tests/phpunit/tests/rest-api/rest-schema-sanitization.php b/tests/phpunit/tests/rest-api/rest-schema-sanitization.php
new file mode 100644
index 0000000000..875a2aafc5
--- /dev/null
+++ b/tests/phpunit/tests/rest-api/rest-schema-sanitization.php
@@ -0,0 +1,89 @@
+<?php
+/**
+ * Unit tests covering schema validation and sanitization functionality.
+ *
+ * @package WordPress
+ * @subpackage REST API
+ */
+
+/**
+ * @group restapi
+ */
+class WP_Test_REST_Schema_Sanitization extends WP_UnitTestCase {
+
+	public function test_type_number() {
+		$schema = array(
+			'type'    => 'number',
+		);
+		$this->assertEquals( 1, rest_sanitize_value_from_schema( 1, $schema ) );
+		$this->assertEquals( 1.10, rest_sanitize_value_from_schema( '1.10', $schema ) );
+		$this->assertEquals( 1, rest_sanitize_value_from_schema( '1abc', $schema ) );
+		$this->assertEquals( 0, rest_sanitize_value_from_schema( 'abc', $schema ) );
+		$this->assertEquals( 0, rest_sanitize_value_from_schema( array(), $schema ) );
+	}
+
+	public function test_type_integer() {
+		$schema = array(
+			'type' => 'integer',
+		);
+		$this->assertEquals( 1, rest_sanitize_value_from_schema( 1, $schema ) );
+		$this->assertEquals( 1, rest_sanitize_value_from_schema( '1.10', $schema ) );
+		$this->assertEquals( 1, rest_sanitize_value_from_schema( '1abc', $schema ) );
+		$this->assertEquals( 0, rest_sanitize_value_from_schema( 'abc', $schema ) );
+		$this->assertEquals( 0, rest_sanitize_value_from_schema( array(), $schema ) );
+	}
+
+	public function test_type_string() {
+		$schema = array(
+			'type' => 'string',
+		);
+		$this->assertEquals( 'Hello', rest_sanitize_value_from_schema( 'Hello', $schema ) );
+		$this->assertEquals( '1.10', rest_sanitize_value_from_schema( 1.10, $schema ) );
+		$this->assertEquals( '1', rest_sanitize_value_from_schema( 1, $schema ) );
+	}
+
+	public function test_type_boolean() {
+		$schema = array(
+			'type' => 'boolean',
+		);
+		$this->assertEquals( true, rest_sanitize_value_from_schema( '1', $schema ) );
+		$this->assertEquals( true, rest_sanitize_value_from_schema( 'true', $schema ) );
+		$this->assertEquals( true, rest_sanitize_value_from_schema( '100', $schema ) );
+		$this->assertEquals( true, rest_sanitize_value_from_schema( 1, $schema ) );
+		$this->assertEquals( false, rest_sanitize_value_from_schema( '0', $schema ) );
+		$this->assertEquals( false, rest_sanitize_value_from_schema( 'false', $schema ) );
+		$this->assertEquals( false, rest_sanitize_value_from_schema( 0, $schema ) );
+	}
+
+	public function test_format_email() {
+		$schema = array(
+			'type'  => 'string',
+			'format' => 'email',
+		);
+		$this->assertEquals( 'email@example.com', rest_sanitize_value_from_schema( 'email@example.com', $schema ) );
+		$this->assertEquals( 'a@b.c', rest_sanitize_value_from_schema( 'a@b.c', $schema ) );
+		$this->assertEquals( 'invalid', rest_sanitize_value_from_schema( 'invalid', $schema ) );
+	}
+
+	public function test_type_array() {
+		$schema = array(
+			'type' => 'array',
+			'items' => array(
+				'type' => 'number',
+			),
+		);
+		$this->assertEquals( array( 1 ), rest_sanitize_value_from_schema( array( 1 ), $schema ) );
+		$this->assertEquals( array( 1 ), rest_sanitize_value_from_schema( array( '1' ), $schema ) );
+	}
+
+	public function test_type_array_as_csv() {
+		$schema = array(
+			'type' => 'array',
+			'items' => array(
+				'type' => 'number',
+			),
+		);
+		$this->assertEquals( array( 1, 2 ), rest_sanitize_value_from_schema( '1,2', $schema ) );
+		$this->assertEquals( array( 1, 2, 0 ), rest_sanitize_value_from_schema( '1,2,a', $schema ) );
+	}
+}