Electrum Patches Bitcoin Wallet Flaw Six Days After First Reported Theft

Electrum released version 4.8.3 on October 24 to fix a flaw that let malicious servers steal bitcoin through fake fee increases. Developers confirmed at least one theft on October 18, six days before the patch. Older builds accept unconfirmed transaction data without signature checks, so an attacker can swap in a fake payment and sign a valid Replace-by-Fee replacement.