CVE-2025-4094 is a critical security vulnerability identified in the DIGITS: WordPress Mobile Number Signup and Login plugin, specifically in versions prior to 8.4.6.1. This plugin facilitates user authentication on WordPress sites via mobile number signup and login using one-time passwords (OTPs). The vulnerability stems from improper restriction of excessive authentication attempts (CWE-307), meaning the plugin does not implement rate limiting or throttling mechanisms on OTP validation attempts. As a result, an attacker can perform brute force attacks against the OTP validation process, systematically trying numerous OTP codes without being blocked or slowed down. This flaw allows attackers to bypass authentication controls, potentially gaining unauthorized access to user accounts. The CVSS v3.1 base score of 9.8 reflects the critical nature of this vulnerability, highlighting its network exploitable vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction needed (UI:N), and its impact on confidentiality, integrity, and availability (all rated high). Although no known exploits are currently reported in the wild, the vulnerability's characteristics make it a prime target for attackers aiming to compromise WordPress sites using this plugin. The lack of patch links suggests that a fix may not yet be publicly available or widely distributed, increasing the urgency for affected organizations to monitor updates closely and consider interim mitigations.

For European organizations, this vulnerability poses a significant risk, especially for businesses and institutions relying on WordPress sites with the DIGITS plugin for user authentication. Successful exploitation can lead to unauthorized account access, data breaches involving personal and sensitive information, and potential disruption of services. Given the critical CVSS score, attackers could compromise user confidentiality and integrity, leading to identity theft, fraud, or unauthorized transactions. Additionally, availability could be impacted if attackers leverage compromised accounts to launch further attacks or disrupt normal operations. The widespread use of WordPress across Europe, including in sectors such as e-commerce, education, and government services, amplifies the potential impact. Organizations handling GDPR-regulated personal data must be particularly cautious, as breaches could result in severe regulatory penalties and reputational damage. The absence of known exploits in the wild currently provides a small window for proactive defense, but the ease of exploitation and lack of authentication requirements mean that attackers could rapidly develop and deploy exploits once the vulnerability becomes widely known.

Immediate mitigation steps include disabling the DIGITS plugin if feasible until a patch is available. Organizations should monitor official plugin repositories and vendor communications for security updates or patches addressing this vulnerability. Implementing web application firewalls (WAFs) with custom rules to detect and block excessive OTP validation attempts can provide a temporary protective layer. Rate limiting at the server or application level should be enforced to restrict the number of OTP validation requests per IP address or user account within a defined timeframe. Additionally, integrating multi-factor authentication (MFA) methods beyond OTPs can reduce reliance on vulnerable authentication flows. Logging and monitoring authentication attempts for anomalies will help detect brute force activities early. Organizations should also educate users about suspicious login activities and encourage strong security hygiene. Finally, conducting regular security assessments of WordPress plugins and dependencies is recommended to identify and remediate similar vulnerabilities proactively.