What are the security flaws ? I think there aren't many, mainly because it's a decentralised exchange.
There are some points they should develop that is about account security, if the user only has a private key that can not be changed then the possibility to be stolen is very large. this is very dangerous for people affected by phishing links.
second development is a gas arrangement that is not understood by everyone, this is a problem because people who do not like it will leave without wanting to learn more
The third is transactions that often delay up to more than 24 hours, this is a big problem if there is congestion due to large volume increases in the same time (Bottle neck)