In Bitcoin Core through 26.0 and Bitcoin Knots before 25.1.knots20231115, datacarrier size limits can be bypassed by obfuscating data as code (e.g., with OP_FALSE OP_IF), as exploited in the wild by Inscriptions in 2022 and 2023. NOTE: although this is a vulnerability from the perspective of the Bitcoin Knots project, some others consider it "not a bug."

Memory management and protection issues in Bitcoin Core v22 allows attackers to modify the stored sending address within the app's memory, potentially allowing them to redirect Bitcoin transactions to wallets of their own choosing.

Bitcoin Core before 24.1, when debug mode is not used, allows attackers to cause a denial of service (e.g., CPU consumption) because draining the inventory-to-send queue is inefficient, as exploited in the wild in May 2023.

bitcoind in Bitcoin Core through 0.21.0 can create a new file in an arbitrary directory (e.g., outside the ~/.bitcoin directory) via a dumpwallet RPC call. NOTE: this reportedly does not violate the security model of Bitcoin Core, but can violate the security model of a fork that has implemented dumpwallet restrictions

Bitcoin Core 0.16.x before 0.16.2 and Bitcoin Knots 0.16.x before 0.16.2 allow remote denial of service via a flood of multiple transaction inv messages with random hashes, aka INVDoS. NOTE: this can also affect other cryptocurrencies, e.g., if they were forked from Bitcoin Core after 2017-11-15.

Bitcoin Core 0.20.0 allows remote denial of service.

Bitcoin Core before 0.14 allows an attacker to create an ostensibly valid SPV proof for a payment to a victim who uses an SPV wallet, even if that payment did not actually occur. Completing the attack would cost more than a million dollars, and is relevant mainly only in situations where an autonomous system relies solely on an SPV proof for transactions of a greater dollar amount.

bitcoind and Bitcoin-Qt prior to 0.15.1 have a stack-based buffer overflow if an attacker-controlled SOCKS proxy server is used. This results from an integer signedness error when the proxy server responds with an acknowledgement of an unexpected target domain name.

bitcoind and Bitcoin-Qt prior to 0.10.2 allow attackers to cause a denial of service (disabled functionality such as a client application crash) via an "Easy" attack.

bitcoind and Bitcoin-Qt prior to 0.17.1 allow injection of arbitrary data into the debug log via an RPC call.