Improper authentication vulnerability in WordPress versions prior to 5.1.15, 5.2.x prior to 5.2.17, 5.3.x prior to 5.3.14, 5.4.x prior to 5.4.12, 5.5.x prior to 5.5.11, 5.6.x prior to 5.6.10, 5.7.x prior to 5.7.8, 5.8.x prior to 5.8.6, 5.9.x prior to 5.9.5 and 6.0.x prior to 6.0.3 allows a remote unauthenticated attacker to obtain the email address of the user who posted a blog using the WordPress Post by Email Feature.
CWE-287 - Improper Authentication
Improper (or broken) authentication attacks are widespread, and have accounted for many of the worst data breaches in recent years. Improper authentication attacks are a class of vulnerabilities where an attacker impersonates a legitimate user by exploiting weaknesses in either session management or credential management to gain access to the user’s account. This can result in disclosure of sensitive information, and can lead to system compromise, theft, identity theft, and fraud.