céu limpo
- [USD] USD 61,334.95
- [BRL] BRL 320,364.73 [USD] USD 61,334.95 [GBP] GBP 45,901.73 [EUR] EUR 53,605.83
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.
[02/07/2026 18:22] Flávio diz aos EUA que tarifaço daria “vitória política” a Lula - Poder360
[02/07/2026 17:05] TV: alunos pedem transferência após professora denunciar vidro em seu copo - UOL Notícias
[02/07/2026 15:27] 'Religiosa' e 'sem histórico de desconfiança': quem é Paola Cirino, diarista presa após morte de casal de idosos em BH - G1
[02/07/2026 10:11] CVM altera pontualmente Resolução 50 sobre PLD/FTP — Comissão de Valores Mobiliários - www.gov.br
[02/07/2026 22:24] Quase todos os chefes do governo de La Guaira morreram, diz Delcy Rodríguez - CNN Brasil
[02/07/2026 08:58] Pastor Márcio Poncio é preso pela PF em ação contra máfia do cigarro - Correio Braziliense
[02/07/2026 16:34] CSN promete entregar mais 120 km da Transnordestina no Ceará até o fim de 2026 - Diário do Nordeste
[02/07/2026 20:22] Defesa de Bolsonaro pede que STF afaste "falta grave" por arma apreendida - CNN Brasil
[02/07/2026 11:27] Michelle Bolsonaro sinaliza desistência do Senado e amplia crise no PL - CartaCapital
[02/07/2026 18:39] Lula afirma que ponte na Bahia pode abrir espaço para o crime organizado - Revista Oeste