"At first, anyone could spend anyone's coins"?

Question

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?

Answer 1

He might be talking about the "1 Return" bug

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?