URL Redirection to Untrusted Site ('Open Redirect')
The nd-learning plugin before 4.8 for WordPress has a nopriv_ AJAX action that allows modification of the siteurl setting.
CWE-601 - Open Redirect
An open redirect attack employs a URL parameter, HTML refresh tags, or a DOM based location change to exploit the trust of a vulnerable domain to direct the users to a malicious website. The attack could lead to higher severity vulnerabilities such as unauthorized access control, account takeover, XSS, and more.