"At first, anyone could spend anyone's coins"? 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 &quot;expanded upon&quot; 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?
He might be talking about the &quot;1 Return&quot; 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 &quot;1 RETURN&quot; bug?