Re: Full RBF

Here is an example of this attack happening on a Wasabi coinjoin (on testnet) which developer /dev/fd0 just shared with the mailing list and on their Twitter:

Quote from: https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2022-June/020601.html

In Wasabi an attacker can broadcast a transaction spending input used in coinjoin after sending signature in the round. This would result in a coinjoin tx which never gets relayed: https://nitter.net/1440000bytes/status/1540727534093905920

You can see the double spend transaction here: https://mempool.space/testnet/tx/a57e46e8a69752802ca83caa37b32bebcaa2965b5572fa805f2b48f1846fd3df
The third input in this transaction for 0.00006561 tBTC was the same input which was used in the coinjoin transaction as you can see from the screenshots.

The Wasabi client reported the invalid coinjoin as "broadcast".