This indicates an attack attempt against a Cross-Site Scripting (XSS) vulnerability in WordPress CMS.
The vulnerability is caused by inadequate input filtering of html encoded character which leads to XSS vulnerabilities in shortcode function. A remote attacker may be able to exploit this to execute arbitrary script code within the context of the application.
WordPress 5.0 through 5.2.2
System Compromise : Remote attackers can execute arbitrary script code within the context of the target user's browser
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