A couple of weeks back, I've read on the forums what is on the top right now. I didn't bother to read because I use hardware wallet. However, lately, I started to see people in both Reddit and the forums telling that this could lead to a chain split so I'm not sure If this is the usual FUD or It's actually something serious? If that is possible, are we out of the danger zone? do we have enough nodes with 0.17.0, 0.16.3, 0.15.2 or 0.14.3?
I've looked into the the error, and correct me if i'm wrong -- It's basically that Bitcoin Core was unable to detect correctly whether a transaction had been double-spend, or not.
Thus, in Bitcoin Core 0.15.X, 0.16.0, 0.16.1, and 0.16.2, any attempts to double-spend a transaction output within a single transaction inside of a block where the output being spent was created in the same block, the same assertion failure will occur (as exists in the test case which was included in the 0.16.3 patch). However, if the output being double-spent was created in a previous block, an entry will still remain in the CCoin map with the DIRTY flag set and having been marked as spent, resulting in no such assertion. This could allow a miner to inflate the supply of Bitcoin as they would be then able to claim the value being spent twice.
This vulnerability seems pretty huge, but not huge enough for a mining company to let their entire reputation go to waste.
Although, that brings me to another question -- If there was no such "assertion" anymore, could a user somehow doublespend a transaction without the miners being able to identify that it is infact a ‟
double-spend‟ - and thus it being possible that said miners didn't know they were including an already spend transaction?
CCoin map with the DIRTY flag set and having been marked as spent
Or would this prevent that?
“This could lead to a chain split“...
Whether it is still possible or not by network rules to accept/validate a block containing such a transaction -- I'm pretty sure that if any miner right now would mine/include/build such a block, it will be quickly orphaned, as the majority of the miners are not malicious, and the reputation of said miner destroyed.
Therefore it seems pretty unlikely to happen - if it still is even possible in the first place. (
Which i'm pretty curious about? Is it? There's a fairly large share of nodes still running older versions.)
You can see the amount of nodes # per version here,
https://bitnodes.earn.com/nodes/
