In wp-includes/formatting.php in WordPress 3.7 to 5.3.0, the function wp_targeted_link_rel() can be used in a particular way to result in a stored cross-site scripting (XSS) vulnerability. This has been patched in WordPress 5.3.1, along with all the previous WordPress versions from 3.7 to 5.3 via a minor release.
blog.ripstech.com/filter/vulnerabilities/
core.trac.wordpress.org/changeset/46894/trunk
github.com/WordPress/wordpress-develop/commit/1f7f3f1f59567e2504f0fbebd51ccf004b3ccb1d
github.com/WordPress/wordpress-develop/security/advisories/GHSA-xvg2-m2f4-83m7
hackerone.com/reports/509930
seclists.org/bugtraq/2020/Jan/8
wordpress.org/news/2019/12/wordpress-5-3-1-security-and-maintenance-release/
wpvulndb.com/vulnerabilities/9975
www.debian.org/security/2020/dsa-4599
www.debian.org/security/2020/dsa-4677