céu limpo
- [USD] USD 63,499.93
- [BRL] BRL 324,884.72 [USD] USD 63,499.93 [GBP] GBP 47,364.03 [EUR] EUR 54,898.74
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.
[11/06/2026 20:02] PF rejeita nova versão de proposta de delação de Vorcaro - CNN Brasil
[11/06/2026 11:36] Trump diz que vai tomar ilha de Kharg e instalações do Irã - Poder360
[11/06/2026 07:55] A vantagem de Lula na disputa com Flávio Bolsonaro em Pernambuco, segundo pesquisa - CartaCapital
[11/06/2026 18:52] Fazenda refaz cálculos e diz que pautas-bomba do Congresso podem ter impacto fiscal de R$ 111 bilhões por ano - G1
[11/06/2026 07:12] Keiko Fujimori reassume liderança na apuração de votos no Peru - Folha PE
[11/06/2026 16:45] Motta anuncia relator do Projeto de Lei que acaba com a escala 6X1 - Metrópoles
[11/06/2026 15:36] STF dá 60 dias para big techs se adequarem; julgamento é suspenso - CNN Brasil
[11/06/2026 03:30] Após avanço na CCJ, constitucionalidade de redução da maioridade penal gera debate entre especialistas - O Globo
[11/06/2026 19:22] Flávio aciona STF contra Lula por fala sobre enforcamento - Poder360
[11/06/2026 12:57] El Niño chegou e pode ser "muito forte", diz agência dos EUA - CNN Brasil