Description
WordPress is prone to a prototype pollution vulnerability. Exploiting this issue could allow an attacker to inject key/value �properties� into JavaScript objects, potentially allowing for execution of arbitrary JavaScript in a user�s session if they can trick that user into clicking a link. WordPress versions 4.8.x ranging from 4.8 and up to (and including) 4.8.18 are vulnerable.
Remediation
Update to WordPress version 4.8.19 or latest
References
https://github.com/BlackFan/client-side-prototype-pollution/blob/master/pp/jquery-query-object.md
https://wordpress.org/support/wordpress-version/version-4.8.19/