Will fixing this issue bring in more revenue than ignoring it and building a new feature? Or fixing a different issue? If the answer is "no" then the answer is that it doesn't get fixed.
I don't agree with this, because it pre-supposes that there's a limited number of engineers available. The question isn't "shall I pull engineer X off project Y so that he can fix security bugs?", it's "shall I hire an additional engineer to fix security bugs?". The comment above mine suggests the answer to that question is "no, because it's too expensive to do that compared to just paying to clean up security breaches after they happen", which is what I was questioning in my first comment.
When framed correctly (there's effectively an unlimited labour supply for most companies, and effectively a limited demand for staff) then the question becomes "shall we hire an engineer to fix security bugs when we don't need an engineer for anything else?".
In effect, there is, yes. At the very least, there’s more high value work that most companies can do than there are engineers to do said work. There’s a reason literally every leadership course teaches you how to say “no” over and over again.
I think it's more realistic that in any sufficiently large company the bureaucracy is so unwieldy that sensible decisions become difficult to make and implement.