Ghost/ghost/admin/app/validators/reset.js

import PasswordValidator from 'ghost-admin/validators/password';

export default PasswordValidator.create({
    properties: ['newPassword'],

    newPassword(model) {
        let p1 = model.get('newPassword');
        let p2 = model.get('ne2Password');

        if (validator.empty(p1)) {
            model.get('errors').add('newPassword', 'Please enter a password.');
            this.invalidate();
        } else if (!validator.equals(p1, p2)) {
            model.get('errors').add('ne2Password', 'The two new passwords don\'t match.');
            this.invalidate();
        }

        this.passwordValidation(model, p1, 'newPassword');
    }
});