céu limpo
- [USD] USD 79,289.69
- [BRL] BRL 398,502.05 [USD] USD 79,289.69 [GBP] GBP 58,614.90 [EUR] EUR 67,663.44
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.
[13/05/2026 17:49] Flávio Bolsonaro confirma pedido para que Vorcaro financiasse filme sobre o pai, mas nega irregularidades - G1
[13/05/2026 13:23] Veja vídeos de integrantes do governo Lula defendendo a "taxa das blusinhas" - Poder360
[13/05/2026 12:31] Motta acelera PEC da escala 6x1 após acordo com o Planalto - Correio Braziliense
[13/05/2026 10:42] Ônibus municipal do Rio não vai mais aceitar pagamento em dinheiro; entenda a medida e dê sua opinião - O Globo
[13/05/2026 15:06] Cármen Lúcia anuncia saída do TSE - CNN Brasil
[13/05/2026 14:16] Papa Leão XIV ameaça de excomunhão grupo católico ultratradicionalista que defende missas em latim - G1
[13/05/2026 16:26] Carlinhos Cachoeira é preso pela PF no Aeroporto de Congonhas, em SP - CNN Brasil
[13/05/2026 08:00] Quaest: para 43%, Lula saiu mais forte após encontro com Trump - G1
[13/05/2026 14:27] Excesso de peso pode ter contribuído para a queda de avião em BH - Estado de Minas
[13/05/2026 08:23] Os novos números da Quaest na disputa pela presidência - CartaCapital