Bitcoin Core before 0.19.0 might allow remote attackers to execute arbitrary code when another application unsafely passes the -platformpluginpath argument to the bitcoin-qt program, as demonstrated by an x-scheme-handler/bitcoin handler for a .desktop file or a web browser. NOTE: the discoverer states "I believe that this vulnerability cannot actually be exploited."
Bitcoin-Qt 0.5.0.x before 0.5.0.5; 0.5.1.x, 0.5.2.x, and 0.5.3.x before 0.5.3.1; and 0.6.x before 0.6.0rc4 on Windows does not use MinGW multithread-safe exception handling, which allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via crafted Bitcoin protocol messages.
Integer overflow in wxBitcoin and bitcoind before 0.3.11 allows remote attackers to bypass intended economic restrictions and create many bitcoins via a crafted Bitcoin transaction.