I would say that rather than "the government behaves rationally" - that every individual behaves in their best interest.
High-ranking intelligence officials will push for more power, more capabilities, and will scrap things if they become risky.
If there's somebody sufficiently powerful whose career would be threatened from some risk of exploiting the bug, that risk will be taken seriously.
If there's somebody sufficiently powerful whose career would benefit from the government letting people know about that bug, it'll happen. This sounds unlikely, but this isn't my area of expertise and if somebody wants to correct me please do so.
Congress will largely ignore it because it has nothing to do with their constituency, they're mostly technically illiterate, and because they're being lied to anyways.
Daniel Kahneman says this has been proven false in his book Thinking Fast and Slow.
It think it is wrong on two levels. First individual's "perceived best interest" is often very far off of their real interest. Second, individual, and not only a few edge cases, are often not behaving in their best interest, even if we consider it to be their "perceived best interest".
Kahneman listed the three attributes of humans modelized as "econs" in the most common economic model: They are rational, selfish and their taste do not change over time. All three are obviously wrong.
High-ranking intelligence officials will push for more power, more capabilities, and will scrap things if they become risky.
If there's somebody sufficiently powerful whose career would be threatened from some risk of exploiting the bug, that risk will be taken seriously.
If there's somebody sufficiently powerful whose career would benefit from the government letting people know about that bug, it'll happen. This sounds unlikely, but this isn't my area of expertise and if somebody wants to correct me please do so.
Congress will largely ignore it because it has nothing to do with their constituency, they're mostly technically illiterate, and because they're being lied to anyways.
...and so on.