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Value overflow incident

From Satoshipedia, the Satoshi Mail encyclopedia

The value overflow incident was a bug found on 15 August 2010, when a transaction in block 74638 used an integer overflow to create bitcoins out of nothing: two outputs of 92,233,720,368.54 BTC each (the forum report). The bug was fixed within hours.[1]

Response

Satoshi posted an alert within hours: “*** WARNING *** We are investigating a problem. DO NOT TRUST ANY TRANSACTIONS THAT HAPPENED AFTER 15.08.2010 17:05 UTC (block 74638) until the issue is resolved.” (the alert). He committed the fix the same day (“fix for block 74638 overflow output transaction”) and released version 0.3.10, which rejected the bad block (the release post).

Satoshi asked users to stop generating so a corrected branch could overtake the bad one. The next day he wrote: “It looks like we overtook the bad chain somewhere around 74689”, and added code to reorganise the chain automatically (the thread).

Aftermath

A week later Satoshi began building an alert system so that developers could warn every node of an emergency (the post). He later handed the alert key to Gavin Andresen.

See also

References

  1. History of bitcoin, Wikipedia (CC BY-SA 4.0). Retrieved 20 October 2026.

Primary sources

The messages and commits this article draws on, in Satoshi Mail and where they were first published.

  1. overflow bug SERIOUS, BitcoinTalk forum, 15 August 2010. Original source
  2. [bitcoin-list] ALERT - we are investigating a problem, bitcoin-list (SourceForge), 15 August 2010. Original source
  3. fix for block 74638 overflow output transaction, commit by Satoshi Nakamoto, 15 August 2010. Original on GitHub
  4. Version 0.3.10 - block 74638 overflow PATCH!, BitcoinTalk forum, 15 August 2010. Original source
  5. Development of alert system, BitcoinTalk forum, 22 August 2010. Original source

Published by Tyler Howell for Satoshi Mail. Written with AI assistance from the sources listed above and checked against them. Last updated 22 October 2026. Spotted an error? Email itstylerhowell@gmail.com (how articles are made).

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