<p>He might be talking about the <a href="https://sites.google.com/a/virginia.edu/the-evolution-of-bitcoin-scripting-interpreter/bitcoin-core-bugs" rel="nofollow noreferrer">&quot;1 Return&quot; bug</a></p>
<blockquote>
<p>1 RETURN Bug (July 2010)</p>
<p>In July 2010, Satoshi and fellow developer Gavin Andresen received a tip-off about this bug that would have <strong>made it possible to spend anyone else’s Bitcoins</strong>. In the early releases of the Bitcoin Core, OP_RETURN was defined as:</p>
<pre><code>case OP_RETURN:

{

    pc = pend;

}

break;         
</code></pre>
<p>An unlocking script of OP_1 OP_RETURN would then always result in a 1 on the top of the stack, as OP_RETURN would end the script evaluation without modifying whatever was already on the stack. This was fixed by changing the opcode to return false and end the script.</p>
</blockquote>
<p>(my emphasis).</p>
<hr />
<p>Related</p>
<ul>
<li><a href="https://bitcoin.stackexchange.com/q/38037/13866">What is the &quot;1 RETURN&quot; bug?</a></li>
</ul>

CC BY-SA 4.0
2021-01-21T16:28:30.833Z
2021-01-21T16:33:39.813Z
2021-01-21T16:33:39.813Z
RedGrittyBrick
<p>I've been watching this Bitcoin video: <a href="https://youtu.be/ZIugzFygviw?t=294" rel="nofollow noreferrer">https://youtu.be/ZIugzFygviw?t=294</a></p>
<p>At the linked-to timestamp, he claims that:</p>
<blockquote>
<p>Due to bugs, at first, anyone could spend anyone's coins!</p>
</blockquote>
<p>I'm not saying that I think he's lying, but was Bitcoin really that buggy initially? That's honestly a bit shocking to hear for me. I did think that Bitcoin was quite solid from the very first v1.0, and has only been &quot;expanded upon&quot; with BIPs ever since. I did not know that such serious bugs existed early on.</p>
<p>Exactly <em>how</em> early are we talking? I had coins in 2009 or 2010. So, back then, anyone could just spend those even though only I had the private keys? And this extremely serious bug was somehow fixed without breaking Bitcoin?</p>

<bitcoin-core><bitcoin-core-development><history><op-return><anyone-can-spend>
"At first, anyone could spend anyone's coins"?
Infinity
# "At first, anyone could spend anyone's coins"?

(Asked by: username_0 on 2021-01-21)

I've been watching this Bitcoin video: <https://youtu.be/ZIugzFygviw?t=294>

At the linked-to timestamp, he claims that:

> Due to bugs, at first, anyone could spend anyone's coins!

I'm not saying that I think he's lying, but was Bitcoin really that buggy initially? That's honestly a bit shocking to hear for me. I did think that Bitcoin was quite solid from the very first v1.0, and has only been "expanded upon" with BIPs ever since. I did not know that such serious bugs existed early on.

Exactly *how* early are we talking? I had coins in 2009 or 2010. So, back then, anyone could just spend those even though only I had the private keys? And this extremely serious bug was somehow fixed without breaking Bitcoin?

**Tags:** bitcoin-core, bitcoin-core-development, history, op-return, anyone-can-spend


---

## 1 answers

### Answer by username_1 on 2021-01-21. Score: 4

He might be talking about the ["1 Return" bug](https://sites.google.com/a/virginia.edu/the-evolution-of-bitcoin-scripting-interpreter/bitcoin-core-bugs)

> 1 RETURN Bug (July 2010)
>
> In July 2010, Satoshi and fellow developer Gavin Andresen received a tip-off about this bug that would have **made it possible to spend anyone else’s Bitcoins**. In the early releases of the Bitcoin Core, OP\_RETURN was defined as:
>
> ```
> case OP_RETURN:
>
> {
>
>     pc = pend;
>
> }
>
> break;         
>
> ```
>
> An unlocking script of OP\_1 OP\_RETURN would then always result in a 1 on the top of the stack, as OP\_RETURN would end the script evaluation without modifying whatever was already on the stack. This was fixed by changing the opcode to return false and end the script.

(my emphasis).

---

Related

* [What is the "1 RETURN" bug?](https://bitcoin.stackexchange.com/q/38037/13866)


---

