CVE-2018-20838
ampforwp_save_steps_data in the AMP for WP plugin before 0.9.97.21 for WordPress allows stored XSS.
Date published : 2019-05-13
https://ampforwp.com/critical-security-issues-has-been-fixed-in-0-9-97-20-version/
https://plugins.trac.wordpress.org/browser/accelerated-mobile-pages/trunk/changelog.txt