hypothetically, an application could be available in the Play Store (assuming it bypasses Google's Bouncer and malware filter), that could gain full (root) rights to any phone utilizing this chipset and affected kernels.
Practically, I think this would be a fairly simple thing for Google to filter for (if they don't already). The larger target here is that the Exynos 4 based S3's are the international variant. Couple that with the proliferation of Android in China and surrounding countries, and the abundance of rogue apps and market-like sources out there (including warez repos). This presents a mighty juicy target for data compromise, hacking, or usage of this exploit as a vector for more traditional malware behavior (ie silently install pay-for-sms spam software, etc).