céu limpo
- [USD] USD 80,626.59
- [BRL] BRL 396,956.93 [USD] USD 80,626.59 [GBP] GBP 59,168.79 [EUR] EUR 68,473.82
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.
[06/05/2026 21:07] Câmara aprova fundo de R$ 5 bi e controle da União sobre minerais críticos - Poder360
[06/05/2026 21:36] Trump diz "I love you" em ligação para Lula antes de reunião; veja como foi - NSC Total
[06/05/2026 12:56] Defesa de Vorcaro entrega proposta de delação à PF e PGR; entenda os próximos passos - CartaCapital
[06/05/2026 23:26] Queda de égua em adutora faz fake news sobre Copasa se espalharem nas redes - Estado de Minas
[06/05/2026 18:42] Avião transportando passageiros com hantavírus faz parada de emergência - CNN Brasil
[06/05/2026 21:39] Prisão de Thiago Ávila aprofunda crise diplomática, mas Itamaraty descarta rompimento com Israel - CartaCapital
[07/05/2026 07:03] Fabio Serapião: Ciro Nogueira é alvo de busca da PF no caso Master - UOL Notícias
[06/05/2026 15:44] Quaest: Lula lidera em Minas no primeiro turno - Estado de Minas
[06/05/2026 19:53] Brasil terá fortes rajadas de vento entre 6 e 10 de maio - Climatempo
[06/05/2026 20:06] Mulher esfaqueia cabeleireiro por corte de cabelo: 'parecendo o Cebolinha' - Correio Braziliense