This is why the assumption that “open source code is more likely to be closely audited for vulnerabilities” is not true (even for incredibly core/important projects with a wide scope) and is potentially dangerous to rely on.
> This is why the assumption that “open source code is more likely to be closely audited for vulnerabilities” is not true...
That is a safe assumption, otherwise you'd have to believe that non-open source code is more closely audited - at greater expense, because businesses secretly prioritize security.