Cross-site scripting (XSS) vulnerability in the Google Analytics by Yoast (google-analytics-for-wordpress) plugin before 5.1.3 for WordPress allows remote attackers to inject arbitrary web script or HTML via the "Manually enter your UA code" (manual_ua_code_field) field in the General Settings.
https://wpvulndb.com/vulnerabilities/7692
https://wordpress.org/plugins/google-analytics-for-wordpress/changelog/
https://twitter.com/yoast/status/537569224307511296