The mails in the pointed-to threads indicate that commits by those UMin people made it to stable; it does not say that commits which introduce bugs made it to stable - it is following a decision/suggestion to back out all patches by these people to the kernel.

There is further indication that the patches to revert are not mostly/not at all vulnerability-introducing patches in a message by "Steve" which says:

> The one patch from Greg's reverts that affects my code was actually a legitimate fix

So, again, while it is still theoretically possible that vulnerabilities were introduced into stable, that is not known to be the case.