chuva fraca
- [USD] USD 59,301.34
- [BRL] BRL 308,135.70 [USD] USD 59,301.34 [GBP] GBP 44,963.58 [EUR] EUR 52,209.49
Price index provided by blockchain.info. - After Bitcoin Core 0.14.0 and before Bitcoin Core 29.0, validating a specially-crafted block may cause the node to access previously freed memory.
During validation, necessary data required for checking inputs for each transaction is pre-calculated and cached. For specially crafted invalid blocks, it was possible for this data to be destroyed while it was still being accessed by a background validation thread. An attacker capable of mining a block with sufficient proof-of-work could have exploited this to crash victim nodes. Because of the nature of use-after-free bugs, it is possible that the crash could have been used for remote code execution, though constraints on the input (block) data make this unlikely.
This issue is considered High severity.
Details
By default, script validation for new blocks is dispatched to background threads via a vector ofCScriptCheckfunctors. Each CScriptCheck holds a pointer to aPrecomputedTransactionDataobject which stores some data needed by each input in the transaction. Because it stores a pointer and not the data itself, care must be taken to ensure that thePrecomputedTransactionDataoutlives theCScriptCheck.
The script checks lifetime is enforced by an RAII class,CCheckQueueControl. However, the control is intantiated before the precomputed transaction data. Because local objects in C++ are destructed in reverse order of construction, this means the vector ofPrecomputedTransactionDatais destroyed before theCCheckQueueControl.
This is not an issue when the block is valid, asCCheckQueueControl::Wait()will be called before the function returns and thePrecomputedTransactionDatagets destroyed. However, in case of an early return (when a separate check fails) a background script thread may read the precomputed transaction data after it was destroyed. An attacker could exploit this to crash victim nodes at the expense of a valid PoW at tip.
Attribution
Cory Fields (MIT DCI) discovered this vulnerability and responsibly disclosed it in a detailed report containing a proof of concept for reproduction and a proposed mitigation.
Timeline
- 2024-11-02 Cory Fields privately reports the bug
- 2024-11-06 Pieter Wuille pushes a covert fix to already open PR #31112 which works around the issue by removing the early returns
- 2024-12-03 PR #31112 is merged
- 2025-04-12 Bitcoin Core version 29.0 is released with a fix
- 2026-04-19 The last vulnerable Bitcoin Core version (28.x) goes end of life
- 2026-05-05 Public disclosure.
[25/06/2026 18:06] Japão x Suécia: onde assistir ao vivo, horário, palpite e escalações do jogo da Copa do Mundo - ND Mais
[25/06/2026 19:39] Mulher de jogador de futebol é encontrada morta em meio a escombros após terremoto na Venezuela; filha foi resgatada - G1
[25/06/2026 19:58] Mendonça cita risco à segurança de Vorcaro ao autorizar transferência - Poder360
[25/06/2026 18:06] Área técnica do STF aponta prevenção de Mendonça no caso "Dark Horse" - CNN Brasil
[25/06/2026 19:09] PGR rejeita proposta de delação de ex-presidente do BRB - CNN Brasil
[25/06/2026 15:39] Flávio Bolsonaro posta vídeo em resposta a Michelle e retira trecho sobre ligação não atendida; veja - Estadão
[25/06/2026 13:39] Cotada, Marília Campos chama de “equívoco” candidatura do PT em MG - Poder360
[25/06/2026 20:02] SP registra a menor temperatura máxima para junho em 30 anos - CNN Brasil
[25/06/2026 14:20] PGR diz que apreensão de arma de Bolsonaro não indica descumprimento de regras - Correio Braziliense
[25/06/2026 18:27] Lula vai gastar mais R$ 5 bilhões para concluir obra parada desde o governo Dilma - Revista Oeste