Ultimate Member < 2.11.3 - Contributor+ Account Takeover via Shortcode Template Tag

Description

The plugin is vulnerable to Sensitive Information Exposure due to the '{usermeta:password_reset_link}' template tag being processed within post content via the '[um_loggedin]' shortcode, which generates a valid password reset token for the currently logged-in user viewing the page. This makes it possible for authenticated attackers, with Contributor-level access and above, to craft a malicious pending post that, when previewed by an Administrator, generates a password reset token for the Administrator and exfiltrates it to an attacker-controlled server, leading to full account takeover.