An exploit? Simply because an app is popping up ads and/or prompting you to install otherwise unwanted bloatware sounds more like a common occurrence with a lot of apps, as oppose to actually being an actual exploit. Some developers will resort to doing things that may be questionably unethical but in our increasingly-perverted capitalist culture still legal to do.
If you installed an app that's too bloated with ads and crapware, just stop using it and uninstall it. It's your choice, just weigh the positives against the negatives. Not knowing just which app or apps you're referring to, hopefully there are equivalent substitutes that aren't so problematic. Or if the app has a pay-for version, the free version might be its ad-heavy version, and you just need to pay for it.
If it's an app that came pre-installed on your phone, you're essentially stuck with it. With system-level apps you can't readily Uninstall them but with some you can at least Disable them. At that point, at least they're no longer active and not able to mess things up in the background.
