A reattach is defined as follows:
Reattach: The process of reattaching a transaction is simply doing the proof of work and tip selection process to reattach the transaction to a different part of the Tangle. Reattach once every 30 minutes that a transaction remains pending, and then if still pending after 5 reattachments be sure to contact the sender to verify that the transaction wasn’t double spent.
Given that the inputs have already been signed and a web server is listening for reattaches, could the server then:
- Detect a reattach
- Stop the transaction (don't propagate it).
- Sign a new stealing transaction with the address private key?
Additionally, could other nodes in the network use a found address key from a reattach to send a higher priority successful double spend by utilizing a much higher Minimum Weight Magnitude and sending it faster through a larger set of neighbors to the network?
Is the use of reattaches from failed Trinity transactions already exposing this vulnerability to users?
If not, what safeguards prevent this from happening?