Description
jQuery before 3.4.0, as used in Drupal, Backdrop CMS, and other products, mishandles jQuery.extend(true, {}, ...) because of Object.prototype pollution. If an unsanitized source object contained an enumerable __proto__ property, it could extend the native Object.prototype.
Remediation
References
Related Vulnerabilities
WordPress Plugin Realty by BestWebSoft Cross-Site Scripting (1.0.9)
WordPress Plugin Ceceppa Multilingua Unspecified Vulnerability (1.5.3)
WordPress Plugin Sliding Recent Posts Cross-Site Request Forgery (1.0)
SugarCRM Improper Control of Generation of Code ('Code Injection') Vulnerability (CVE-2019-17307)