CVE-2026-18469 in Login & Register Forms Plugin
Summary
by MITRE • 08/10/2026
The Login & Register Forms WordPress plugin before 4.0.2 does not enforce its password reset attempt limit against a server-derived value, keying both the verification code and the per-source attempt counter on client-controlled data, allowing unauthenticated attackers to reset the limit at will and brute-force the code to take over any account, including administrators, when the verification-code reset mode is enabled.
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Analysis
by VulDB Data Team • 08/10/2026
The vulnerability in the Login & Register Forms WordPress plugin affects versions prior to 4.0.2 and represents a critical authentication bypass flaw that undermines the plugin's security mechanisms. This issue stems from improper implementation of password reset attempt limiting functionality where the system relies on client-controlled data rather than server-derived values for tracking reset attempts. The vulnerability specifically impacts the verification code reset mode, creating a pathway for unauthenticated attackers to systematically exploit account recovery mechanisms without facing legitimate rate limiting controls.
The technical flaw manifests in how the plugin manages its internal counters and verification codes during password reset operations. When an attacker initiates a password reset request, the system should maintain server-side tracking of attempt counts and reset limits to prevent brute force attacks. However, the vulnerable implementation keys both the verification code generation and per-source attempt counter on data that originates from the client side, such as IP addresses or session identifiers that can be easily manipulated or spoofed. This design flaw allows malicious actors to reset the attempt counters at will by simply changing their client-side parameters, effectively bypassing any intended rate limiting protections.
The operational impact of this vulnerability extends beyond simple account compromise, particularly when targeting administrator accounts. Attackers can leverage this weakness to perform unlimited brute force attempts against password reset codes without triggering any meaningful security controls. The ability to reset the attempt limit continuously enables systematic enumeration of verification codes, making it possible for attackers to gain unauthorized access to any user account within the WordPress installation. This represents a significant escalation from typical credential stuffing attacks to full account takeover scenarios with potentially severe consequences for system integrity and data confidentiality.
The vulnerability aligns with several cybersecurity standards and frameworks, particularly CWE-305 Authentication Bypass by Primary Weakness which addresses authentication mechanisms that can be circumvented through flawed implementation. Additionally, this flaw maps to ATT&CK technique T1110.003 Brute Force: Password Guessing where adversaries attempt multiple password or code combinations to gain unauthorized access. The issue also reflects broader concerns around improper input validation and insufficient server-side state management in web applications, which are commonly addressed through secure coding practices outlined in OWASP Top Ten and NIST cybersecurity guidelines.
Mitigation strategies should prioritize immediate patching of the plugin to version 4.0.2 or later where the vulnerability has been resolved through proper implementation of server-side attempt limiting. Organizations should also implement additional security measures including IP-based rate limiting at the web server level, enhanced monitoring of authentication attempts, and consideration of multi-factor authentication mechanisms. Network-level controls such as firewall rules that limit the frequency of password reset requests from individual IP addresses can provide additional defense in depth. Administrators should also review and validate account recovery settings to ensure that verification codes are properly secured with sufficient entropy and that appropriate logging is enabled for suspicious activity detection.
The remediation process requires careful attention to the plugin's configuration and integration within the WordPress environment, as improper implementation of security controls could introduce new vulnerabilities or break existing functionality. Security teams should conduct thorough testing of the patched version to ensure that legitimate users can still perform password resets while maintaining appropriate security controls. Regular vulnerability scanning and penetration testing should be implemented to identify similar issues in other plugins or custom code components that may exhibit similar flawed authentication mechanisms. Continuous monitoring of authentication logs and implementation of automated alerting systems will help detect potential exploitation attempts before they succeed in compromising accounts.
Organizations using this plugin should also consider implementing additional security layers such as CAPTCHA verification for password reset requests, account lockout mechanisms after failed attempts, and enhanced session management controls. The vulnerability demonstrates the critical importance of server-side validation and proper state management in authentication systems, where client-side data should never be trusted for security-critical operations. Implementation of these measures will significantly reduce the attack surface and provide more robust protection against similar credential-based attacks targeting WordPress installations.