diff --git a/src/wp-includes/formatting.php b/src/wp-includes/formatting.php
index acc8de9188..1251508d2e 100644
--- a/src/wp-includes/formatting.php
+++ b/src/wp-includes/formatting.php
@@ -5403,6 +5403,33 @@ function wp_unslash( $value ) {
 	return stripslashes_deep( $value );
 }
 
+/**
+ * Adds slashes to only string values in an array of values.
+ *
+ * This should be used when preparing data for core API that expects slashed data.
+ * This should not be used to escape data going directly into an SQL query.
+ *
+ * @since 5.3.0
+ *
+ * @param mixed $value Scalar or array of scalars.
+ * @return mixed Slashes $value
+ */
+function wp_slash_strings_only( $value ) {
+	return map_deep( $value, 'addslashes_strings_only' );
+}
+
+/**
+ * Adds slashes to only string values.
+ *
+ * @since 5.3.0
+ *
+ * @param mixed $value
+ * @return mixed
+ */
+function addslashes_strings_only( $value ) {
+	return is_string( $value ) ? addslashes( $value ) : $value;
+}
+
 /**
  * Extract and return the first URL from passed content.
  *
diff --git a/src/wp-includes/rest-api/fields/class-wp-rest-meta-fields.php b/src/wp-includes/rest-api/fields/class-wp-rest-meta-fields.php
index b3ea89a86e..411fc5460c 100644
--- a/src/wp-includes/rest-api/fields/class-wp-rest-meta-fields.php
+++ b/src/wp-includes/rest-api/fields/class-wp-rest-meta-fields.php
@@ -365,7 +365,7 @@ abstract class WP_REST_Meta_Fields {
 			}
 		}
 
-		if ( ! update_metadata( $meta_type, $object_id, wp_slash( $meta_key ), wp_slash( $value ) ) ) {
+		if ( ! update_metadata( $meta_type, $object_id, wp_slash( $meta_key ), wp_slash_strings_only( $value ) ) ) {
 			return new WP_Error(
 				'rest_meta_database_error',
 				/* translators: %s: Custom field key. */
diff --git a/tests/phpunit/tests/rest-api/rest-post-meta-fields.php b/tests/phpunit/tests/rest-api/rest-post-meta-fields.php
index 2007e77ef2..6b483ff0c9 100644
--- a/tests/phpunit/tests/rest-api/rest-post-meta-fields.php
+++ b/tests/phpunit/tests/rest-api/rest-post-meta-fields.php
@@ -2264,6 +2264,152 @@ class WP_Test_REST_Post_Meta_Fields extends WP_Test_REST_TestCase {
 		self::assertFalse( $registered );
 	}
 
+	/**
+	 * @ticket 48264
+	 */
+	public function test_update_array_of_ints_meta() {
+		$this->grant_write_permission();
+		register_post_meta(
+			'post',
+			'items',
+			array(
+				'single'       => true,
+				'type'         => 'array',
+				'show_in_rest' => array(
+					'schema' => array(
+						'items' => array(
+							'type' => 'integer',
+						),
+					),
+				),
+			)
+		);
+
+		$request = new WP_REST_Request( 'PUT', sprintf( '/wp/v2/posts/%d', self::$post_id ) );
+		$request->set_body_params(
+			array(
+				'meta' => array(
+					'items' => array( 1, 2, 3 ),
+				),
+			)
+		);
+
+		rest_get_server()->dispatch( $request );
+		$response = rest_get_server()->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+	}
+
+	/**
+	 * @ticket 48264
+	 */
+	public function test_update_array_of_ints_meta_stored_strings_are_updated() {
+		$this->grant_write_permission();
+		register_post_meta(
+			'post',
+			'items',
+			array(
+				'single'       => true,
+				'type'         => 'array',
+				'show_in_rest' => array(
+					'schema' => array(
+						'items' => array(
+							'type' => 'integer',
+						),
+					),
+				),
+			)
+		);
+
+		update_post_meta( self::$post_id, 'items', array( '1', '2', '3' ) );
+
+		$request = new WP_REST_Request( 'PUT', sprintf( '/wp/v2/posts/%d', self::$post_id ) );
+		$request->set_body_params(
+			array(
+				'meta' => array(
+					'items' => array( 1, 2, 3 ),
+				),
+			)
+		);
+
+		$response = rest_get_server()->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+		$this->assertSame( array( 1, 2, 3 ), get_post_meta( self::$post_id, 'items', true ) );
+	}
+
+	/**
+	 * @ticket 48264
+	 */
+	public function test_update_array_of_ints_meta_string_request_data_is_set_as_ints() {
+		$this->grant_write_permission();
+		register_post_meta(
+			'post',
+			'items',
+			array(
+				'single'       => true,
+				'type'         => 'array',
+				'show_in_rest' => array(
+					'schema' => array(
+						'items' => array(
+							'type' => 'integer',
+						),
+					),
+				),
+			)
+		);
+
+		update_post_meta( self::$post_id, 'items', array( 1, 2, 3 ) );
+
+		$request = new WP_REST_Request( 'PUT', sprintf( '/wp/v2/posts/%d', self::$post_id ) );
+		$request->set_body_params(
+			array(
+				'meta' => array(
+					'items' => array( '1', '2', '3' ),
+				),
+			)
+		);
+
+		$response = rest_get_server()->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+		$this->assertSame( array( 1, 2, 3 ), get_post_meta( self::$post_id, 'items', true ) );
+	}
+
+	/**
+	 * @ticket 48264
+	 */
+	public function test_update_array_of_ints_meta_string_request_data_and_string_stored_data() {
+		$this->grant_write_permission();
+		register_post_meta(
+			'post',
+			'items',
+			array(
+				'single'       => true,
+				'type'         => 'array',
+				'show_in_rest' => array(
+					'schema' => array(
+						'items' => array(
+							'type' => 'integer',
+						),
+					),
+				),
+			)
+		);
+
+		update_post_meta( self::$post_id, 'items', array( '1', '2', '3' ) );
+
+		$request = new WP_REST_Request( 'PUT', sprintf( '/wp/v2/posts/%d', self::$post_id ) );
+		$request->set_body_params(
+			array(
+				'meta' => array(
+					'items' => array( '1', '2', '3' ),
+				),
+			)
+		);
+
+		$response = rest_get_server()->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+		$this->assertSame( array( 1, 2, 3 ), get_post_meta( self::$post_id, 'items', true ) );
+	}
+
 	/**
 	 * Internal function used to disable an insert query which
 	 * will trigger a wpdb error for testing purposes.
diff --git a/tests/qunit/fixtures/wp-api-generated.js b/tests/qunit/fixtures/wp-api-generated.js
index b8217e729b..2b5f8d38e9 100644
--- a/tests/qunit/fixtures/wp-api-generated.js
+++ b/tests/qunit/fixtures/wp-api-generated.js
@@ -2304,7 +2304,7 @@ mockedApiResponse.Schema = {
                 }
             ]
         },
-        "/wp/v2/media/(?P<id>[\\d+])/post-process": {
+        "/wp/v2/media/(?P<id>[\\d]+)/post-process": {
             "namespace": "wp/v2",
             "methods": [
                 "POST"