One of the users in the Gallery support forums (Rockman_Ghost) came across a possible security issue when Gallery is in debug mode and configured with email features enabled. This affects very few production Galleries. Read on for more details.
When Gallery is in debug mode, it prints the contents of all emails sent from it (as a tool for debugging). However, this means it also prints emails going out to users who forget their password. It is obviously not intended for anyone to see the contents of these 'forgotten password' emails as then anyone could change a user's password.
We don't recommend keeping debug mode on for production Galleries anyway and this issue has been fixed in the upcoming release of 1.4.4; however, if you are currently running a production Gallery in debug mode, we strongly suggest that you disable this function, as it should only be used for developers or people debugging their Galleries.