I was looking for few papers on arXiv and found very interesting paper with title "Congestion Attacks in Payment Channel Networks"
[1] and just submitted 2 days ago.
They mention 2 possible attack which are :
1. Attacking whole network by relaying a transaction to the attacker himself. Surprisingly, similar method is suggested to improve user's privacy
[2] 2. Isolate a single node/hub by creating multiple payment request through attacked node/hub (i don't really understand this part)
What do you think?
Source :
1.
https://arxiv.org/abs/2002.065642.
https://bitcoinmagazine.com/articles/paying-yourself-self-payments-could-be-a-key-to-lightning-privacy