céu limpo
- [USD] USD 81,540.93
- [BRL] BRL 400,153.95 [USD] USD 81,540.93 [GBP] GBP 59,951.09 [EUR] EUR 69,252.14
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.
[11/05/2026 20:26] Explosão destrói ao menos dez imóveis em área residencial na Zona Oeste de SP - O Globo
[11/05/2026 11:58] Paulinho da Força responde fala de Flávio sobre "jogo combinado" com Moraes - CNN Brasil
[11/05/2026 19:16] Nunes Marques é sorteado como relator de pedido de Bolsonaro para anular condenação - CartaCapital
[11/05/2026 17:24] Hantavírus mata quase metade dos infectados no Brasil: veja onde há mais risco (e por que não tem relação com surto em navio de cruzeiro) - BBC
[11/05/2026 14:03] Defesa de Ciro Nogueira: Kakay nega atrito e diz que saída foi consensual - Correio Braziliense
[11/05/2026 10:47] Racha na direita: Salles ataca Eduardo Bolsonaro em disputa pelo Senado - Estado de Minas
[11/05/2026 12:59] Minas Gerais confirma primeira morte por hantavírus em 2026 - Agência Brasil
[11/05/2026 18:58] Grevistas de Unesp, USP e Unicamp têm confronto com bolsonaristas - Poder360
[11/05/2026 15:45] Guarda municipal é preso após matar esposa na festa do casamento em Campinas - Jovem Pan
[11/05/2026 08:13] Ministro Nunes Marques convida Bolsonaro para cerimônia de posse na Presidência do TSE - R7