CVE-2025-59943: 
PHP vulnerability analysis and mitigation

CVE-2025-59943 affects phpMyFAQ, an open source FAQ web application. The vulnerability was discovered and disclosed on October 3, 2025, impacting versions 4.0-nightly-2025-10-03 and below. The issue stems from the application's failure to enforce email address uniqueness during user registration, allowing multiple distinct accounts to be created with the same email address (GitHub Advisory, NVD).

The vulnerability has been assigned a CVSS v3.1 base score of 8.1 (High) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N. The issue is rooted in an account management logic flaw where the application fails to validate email uniqueness during the registration process. The vulnerability specifically affects the user registration functionality, where the system does not check for existing email addresses before creating new accounts (GitHub Advisory).

The vulnerability can lead to several serious consequences: data integrity loss due to multiple accounts being mapped to one email breaking auditability, password reset ambiguity when the reset flow relies on email only, potential privilege escalation if one account with the same email has admin privileges, and possible spam or DoS attacks through mass registration of accounts with a single email address. The impact is particularly severe for systems where email is used as a unique identifier for password resets, notifications, and administrative actions (GitHub Advisory).

The vulnerability has been fixed in version 4.0.13 of phpMyFAQ. The fix implements email validation logic in two key functions: phpMyFAQ\Helper\RegistrationHelper::createUser and phpMyFAQ\User::createUser. The patch adds checks to verify email uniqueness before allowing new user registration (GitHub Commit).