CVE-2025-3844 is a critical authentication bypass vulnerability affecting the PeproDev Ultimate Profile Solutions plugin for WordPress, specifically versions 1.9.1 through 7.5.2. The root cause lies in the plugin's handel_ajax_req() function, which improperly restricts access to the change_user_meta functionality. This flaw allows unauthenticated attackers to manipulate user metadata, notably setting a one-time password (OTP) code arbitrarily. By doing so, attackers can bypass normal authentication mechanisms and log in as any user on the affected WordPress site, including users with administrative privileges. The vulnerability is classified under CWE-288, which pertains to authentication bypass using alternate paths or channels. The CVSS v3.1 base score is 9.8, indicating a critical severity with network attack vector, no privileges required, no user interaction needed, and full impact on confidentiality, integrity, and availability. No public exploits are currently known in the wild, but the high severity and ease of exploitation make this a significant threat to WordPress sites using this plugin. The vulnerability enables attackers to fully compromise affected sites, potentially leading to data theft, site defacement, malware deployment, or pivoting to internal networks.

For European organizations, this vulnerability poses a severe risk, especially for those relying on WordPress sites with the PeproDev Ultimate Profile Solutions plugin. Successful exploitation can lead to unauthorized administrative access, resulting in data breaches involving personal data protected under GDPR, disruption of services, and reputational damage. Organizations in sectors such as e-commerce, government, healthcare, and finance that use WordPress for customer portals or internal tools are particularly at risk. The ability to bypass authentication without any user interaction or privileges means attackers can automate attacks at scale, potentially compromising multiple sites rapidly. This could also facilitate supply chain attacks if compromised sites serve as platforms for distributing malicious content or malware. The impact extends beyond the individual site to the broader ecosystem, including customers and partners, increasing legal and compliance risks for European entities.

Immediate mitigation involves updating the PeproDev Ultimate Profile Solutions plugin to a patched version once released by the vendor. Until a patch is available, organizations should consider disabling or removing the plugin to eliminate exposure. Implementing Web Application Firewalls (WAFs) with custom rules to block or monitor suspicious AJAX requests targeting the change_user_meta functionality can reduce risk. Restricting access to the WordPress admin and AJAX endpoints via IP whitelisting or VPN-only access can limit attacker reach. Regularly auditing user accounts and monitoring logs for unusual login patterns or metadata changes can help detect exploitation attempts. Employing multi-factor authentication (MFA) at the WordPress login level, independent of the plugin’s OTP mechanism, adds an additional security layer. Organizations should also review and tighten user permissions to minimize the impact of potential account compromises. Finally, maintaining up-to-date backups and having an incident response plan tailored to web application compromises will aid in rapid recovery if exploitation occurs.