The Bloom Filter implementation in bitcoind and Bitcoin-Qt 0.8.x before 0.8.4rc1 allows remote attackers to cause a denial of service (divide-by-zero error and daemon crash) via a crafted sequence of messages.

Unspecified vulnerability in bitcoind and Bitcoin-Qt 0.8.x allows remote attackers to cause a denial of service (memory consumption) via a large amount of tx message data.

The HTTPAuthorized function in bitcoinrpc.cpp in bitcoind 0.8.1 provides information about authentication failure upon detecting the first incorrect byte of a password, which makes it easier for remote attackers to determine passwords via a timing side-channel attack.

bitcoind and Bitcoin-Qt 0.8.x before 0.8.1 do not enforce a certain block protocol rule, which allows remote attackers to bypass intended access restrictions and conduct double-spending attacks via a large block that triggers incorrect Berkeley DB locking in older product versions.

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.

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 make it easier for remote attackers to obtain potentially sensitive information about returned change by leveraging certain predictability in the outputs of a Bitcoin transaction.

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.

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 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 OP_CHECKSIG script opcodes.