<p>Yes, I did some double-spends playing on-chain games. It was years ago when a game (for example luckyb.it) accepted transaction with high-S-value, but most of pools did not include it into the block. The strategy was: send a bet with high-S-value, doublespend it if loss or wait several hours for a pool what confirm it on win.</p>
<p>As far as I remember, successful doublespend was performed by pool operator (I do not remember which one) when Bitcion forked in 2013 (0.7 to 0.8 version upgrade)</p>

CC BY-SA 4.0
2021-01-02T19:57:49.763Z
2021-01-02T19:57:49.763Z
amaclin
<p>If it would be possible to doublespend bitcoin, it probably wouldn't have that much value as it have, right? But some of the wallets (BRD and Edge if I remember correctly) had this UI that portrayed unconfirmed transactions as already confirmed which led to some confusion of clients of these wallets and anectodal evidence shows that these wallet's clients might have lost money in the deal.</p>
<p>If you are looking for something closely related to bitcoin, but not bitcoin, I'd check the issues of (~2018) exploit of bad integration of Omni layer on the exchange. As some exchange (forgot the name) wasn't looking at omni layer status of verification (True/False for doublespends) but just payload of OP_RETURN script, it was possible to doublespend it, and this problem was found by some group of researchers.</p>

CC BY-SA 4.0
2021-01-02T10:14:42.037Z
It is possible to double spend bitcoin, and it's easier if you have the support of a (few) pools
MCCCS
CC BY-SA 4.0
2021-01-02T03:47:10.870Z
2021-01-02T03:47:10.870Z
Tony Sanak
<p>Do you know any real-world examples of double-spends, where the second transaction was accepted to the block?</p>
<p>There's <a href="https://doublespend.cash/" rel="nofollow noreferrer">https://doublespend.cash/</a> for BCH but for BTC I would like some examples where the <em>second transaction</em> is accepted. (And this website shows all occurences of double-spends. I just want some successful ones.)</p>

CC BY-SA 4.0
2021-01-02T08:06:32.760Z
what is high-value? is is $1k?
amaclin
CC BY-SA 4.0
2021-01-02T10:11:49.977Z
@amaclin I removed it, value doesn't matter. A transaction is a transaction.
MCCCS
<transactions><doublespend>
Notable examples of double-spends
MCCCS
# Notable examples of double-spends

(Asked by: username_0 on 2021-01-01)

Do you know any real-world examples of double-spends, where the second transaction was accepted to the block?

There's <https://doublespend.cash/> for BCH but for BTC I would like some examples where the *second transaction* is accepted. (And this website shows all occurences of double-spends. I just want some successful ones.)

**Tags:** transactions, doublespend

> **Comments:**
> **username_1**: what is high-value? is is $1k?  
> **username_0**: @username_1 I removed it, value doesn't matter. A transaction is a transaction.  

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## 2 answers

### Answer by username_1 on 2021-01-02. Score: 1 | Accepted answer

Yes, I did some double-spends playing on-chain games. It was years ago when a game (for example luckyb.it) accepted transaction with high-S-value, but most of pools did not include it into the block. The strategy was: send a bet with high-S-value, doublespend it if loss or wait several hours for a pool what confirm it on win.

As far as I remember, successful doublespend was performed by pool operator (I do not remember which one) when Bitcion forked in 2013 (0.7 to 0.8 version upgrade)


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### Answer by username_2 on 2021-01-02. Score: 0

If it would be possible to doublespend bitcoin, it probably wouldn't have that much value as it have, right? But some of the wallets (BRD and Edge if I remember correctly) had this UI that portrayed unconfirmed transactions as already confirmed which led to some confusion of clients of these wallets and anectodal evidence shows that these wallet's clients might have lost money in the deal.

If you are looking for something closely related to bitcoin, but not bitcoin, I'd check the issues of (~2018) exploit of bad integration of Omni layer on the exchange. As some exchange (forgot the name) wasn't looking at omni layer status of verification (True/False for doublespends) but just payload of OP\_RETURN script, it was possible to doublespend it, and this problem was found by some group of researchers.

> **Comments:**
> **username_0**: It is possible to double spend bitcoin, and it's easier if you have the support of a (few) pools  

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