Samourai Wallet Stonewallx2 0.99.98e allows a denial of service via a P2P coinjoin.

Summary

Samourai Wallet Stonewallx2 0.99.98e allows a denial of service via a P2P coinjoin. The attacker and victim must follow each other's paynym. Then, the victim must try to collaborate with the attacker for a Stonewallx2 transaction. Next, the attacker broadcasts a tx, spending the inputs used in Stonewallx2 before the victim can broadcast the collaborative transaction. The attacker does not signal opt in RBF, and uses the lowest fee rate. This would result in the victim being unable to perform Stonewallx2. (Note that the attacker could use multiple paynyms.)