Impact

Exception messages from internal exceptions (like database exception) are wrapped by \Symfony\Component\Security\Core\Exception\AuthenticationServiceException and propagated through the system to UI. Therefore, some internal system information may leak and be visible to the customer.

A validation message with the exception details will be presented to the user when one will try to log into the shop.

Patches

Has the problem been patched? What versions should users upgrade to?

Workarounds

The src/Sylius/Bundle/UiBundle/Resources/views/Security/_login.html.twig file should be overridden and lines https://github.com/Sylius/Sylius/blob/1.4/src/Sylius/Bundle/UiBundle/Resources/views/Security/_login.html.twig#L13-L17 should be replaced with

        {% if last_error %}
            <div class="ui left aligned basic segment">
                {{ messages.error(last_error.messageKey) }}
            </div>
        {% endif %}

The messageKey field should be used instead of the message.