bitcoind and Bitcoin-Qt 0.8.0 and earlier allow remote attackers to cause a denial of service (electricity consumption) by mining a block to create a nonstandard Bitcoin transaction containing multiple OPCHECKSIG script opcodes.
The alert functionality in bitcoind and Bitcoin-Qt before 0.7.0 supports different character representations of the same signature data, but relies on a hash of this signature, which allows remote attackers to cause a denial of service (resource consumption) via a valid modified signature for a circulating alert.
bitcoind and Bitcoin-Qt before 0.4.9rc2, 0.5.x before 0.5.8rc2, 0.6.x before 0.6.5rc2, and 0.7.x before 0.7.3rc2, and wxBitcoin, do not properly consider whether a block's size could require an excessive number of database locks, which allows remote attackers to cause a denial of service (split) and enable certain double-spending capabilities via a large block that triggers incorrect Berkeley DB locking.
Unspecified vulnerability in bitcoind and Bitcoin-Qt before 0.4.7rc3, 0.5.x before 0.5.6rc3, 0.6.0.x before 0.6.0.9rc1, and 0.6.x before 0.6.3rc1 allows remote attackers to cause a denial of service (process hang) via unknown behavior on a Bitcoin network.
Unspecified vulnerability in bitcoind and Bitcoin-Qt before 0.4.6, 0.5.x before 0.5.5, 0.6.0.x before 0.6.0.7, and 0.6.x before 0.6.2 allows remote attackers to cause a denial of service (block-processing outage and incorrect block count) via unknown behavior on a Bitcoin network.
The penny-flooding protection mechanism in the CTxMemPool::accept method in bitcoind and Bitcoin-Qt before 0.4.9rc1, 0.5.x before 0.5.8rc1, 0.6.0 before 0.6.0.11rc1, 0.6.1 through 0.6.5 before 0.6.5rc1, and 0.7.x before 0.7.3rc1 allows remote attackers to determine associations between wallet addresses and IP addresses via a series of large Bitcoin transactions with insufficient fees.
The CTransaction::FetchInputs method in bitcoind and Bitcoin-Qt before 0.8.0rc1 copies transactions from disk to memory without incrementally checking for spent prevouts, which allows remote attackers to cause a denial of service (disk I/O consumption) via a Bitcoin transaction with many inputs corresponding to many different parts of the stored block chain.