céu limpo
- [USD] USD 59,605.13
- [BRL] BRL 309,118.15 [USD] USD 59,605.13 [GBP] GBP 45,151.96 [EUR] EUR 52,333.42
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.
[28/06/2026 11:43] Esposa e filhos de jogador argentino são encontrados mortos após terremotos na Venezuela - G1
[28/06/2026 09:06] Corpo é encontrado no costão da Niemeyer após cinco dias de buscas por professor de surfe desaparecido no mar - O Globo
[28/06/2026 08:27] Quaest: Lula tem 51% de aprovação entre independentes; 35% das mulheres são anti Flávio Bolsonaro - Revista Fórum
[28/06/2026 06:37] Onda de calor extremo mata 1.000 na França em apenas 3 dias - dw.com
[28/06/2026 11:15] Irmão de Eloá, tenente da Rota baleado segue em estado gravíssimo - UOL Notícias
[28/06/2026 13:25] Irã diz ter atacado alvos ligados aos EUA - CNN Brasil
[28/06/2026 12:24] Mulher morta em Barbacena já havia registrado ocorrência contra o suspeito - Estado de Minas
[27/06/2026 09:14] Veja quem era o casal que morreu após carro cair de viaduto no mar no RJ - Rádio Itatiaia
[27/06/2026 00:01] PT aposta no esquecimento e protela expulsão de vereador ligado ao PCC - Diário do Poder
[28/06/2026 00:00] Copa do Mundo: veja quais capitais terão ponto facultativo ou expediente reduzido no jogo do Brasil - G1