CVE-2025-34077 is a critical authentication bypass vulnerability affecting the WordPress Pie Register plugin developed by Genetech Solutions, specifically versions up to and including 3.7.1.4. This vulnerability allows unauthenticated attackers to impersonate arbitrary users by sending a specially crafted POST request to the plugin's login endpoint. The exploit leverages the manipulation of the 'social_site' parameter set to true and the 'user_id_social_site' parameter to generate a valid WordPress session cookie for any user ID, including those with administrative privileges. Once authenticated as an administrator, the attacker can abuse the plugin's file upload functionality, which lacks proper restrictions on file types (CWE-434), to upload malicious plugins containing arbitrary PHP code. This leads to remote code execution (RCE) on the underlying server, granting the attacker full control over the compromised system. The vulnerability combines multiple weaknesses: improper authentication (CWE-306), unrestricted file upload (CWE-434), and code injection (CWE-94). The CVSS 4.0 base score is 10.0, indicating a critical severity with network attack vector, no required privileges or user interaction, and high impact on confidentiality, integrity, and availability. No patches are currently available, and no known exploits have been observed in the wild yet, but the potential for exploitation is significant due to the ease of attack and the critical impact.

For European organizations, this vulnerability poses a severe threat, especially those relying on WordPress websites with the Pie Register plugin installed. Successful exploitation can lead to complete compromise of web servers, enabling attackers to steal sensitive data, deface websites, deploy ransomware, or use the compromised infrastructure for further attacks such as lateral movement or launching attacks against other targets. Given the widespread use of WordPress across various sectors including government, finance, healthcare, and e-commerce in Europe, the impact could be substantial. Organizations may face data breaches, service outages, reputational damage, and regulatory penalties under GDPR for failing to protect personal data. The ability to bypass authentication and execute arbitrary code without user interaction makes this vulnerability particularly dangerous in automated attack scenarios and targeted campaigns against high-value European entities.

Immediate mitigation steps include disabling or uninstalling the Pie Register plugin until a vendor patch is released. Organizations should monitor web server logs for suspicious POST requests to the login endpoint containing 'social_site=true' and anomalous 'user_id_social_site' values. Implementing Web Application Firewalls (WAFs) with custom rules to block such crafted requests can provide temporary protection. Restricting file upload permissions and validating file types rigorously at the application and server level can reduce the risk of malicious uploads. Additionally, enforcing strict access controls and isolating WordPress instances can limit the blast radius of a potential compromise. Organizations should also conduct thorough audits of WordPress user accounts to detect unauthorized sessions or privilege escalations. Once a patch is available, prompt application of updates is critical. Regular backups and incident response plans should be reviewed and tested to prepare for potential exploitation.