CVE-2021-4073: 
WordPress vulnerability analysis and mitigation

CVE-2021-4073 is an authentication bypass vulnerability discovered in the RegistrationMagic WordPress plugin that affected versions up to and including 5.0.1.7. The vulnerability allowed unauthenticated users to log in as any site user, including administrators, by only knowing their email address or username. The issue was discovered in 2021 and was assigned a critical CVSS score of 9.8 (NVD, WPScan).

The vulnerability stemmed from an insecure implementation of the social login functionality in the plugin's socialloginusing_email() function. The flaw required the login form to have social integration, such as Facebook, and could be exploited by obtaining the security nonce for social login. The vulnerability has been assigned CWE-287 (Improper Authentication) with a CVSS v3.1 base score of 9.8 (CRITICAL) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (WPScan).

The vulnerability allowed attackers to gain unauthorized administrative access to affected WordPress websites. With admin access, attackers could take full control of the website, modify content, install malicious plugins, and access sensitive information (SecMaster).

The vulnerability was fully patched in version 5.0.1.8 of the RegistrationMagic plugin. Website administrators are strongly advised to update to this version or later. Additionally, Wordfence created a firewall rule to protect its customers from attacks targeting this vulnerability (SecMaster).