[lvh]

This is not an uncommon phenomenon and not specific to vuln research. It happens all the time in mathematics, the sciences... [0]

Far more likely: there is a related cause that made two people think to try the same thing at approximately the same time. Someone publishes a new JIT type confusion bug, someone realizes "oh man it never occurred to me that X could trigger bug type Y", they start digging, and...

[0]: https://en.wikipedia.org/wiki/Multiple_discovery

[ChrisCinelli]

Thanks for the comment. I think where I read of the other synchronous discovery was hinting to what you wrote but I deliberately wanted to hear about the probability of researchers being compromised.

Maybe this is not the case but if somebody has powerful means, knowledge on how do successful targeted attacks, and access to the right 0 days, it would make sense that can use their resources to find other 0 days in this way.