Now - is that very likely? Probably not, even if such a vulnerability exists modern exploit mitigation tactics often are able to prevent it from becoming very harmful. But it's worst case.
Android itself has had big media decode vulnerabilities in the past (looking at you libstagefright) but they basically turned out not to be readily exploitable due to ASLR on modern devices.
That's what the optimist says.
The pessimist says, "Android itself has had big media decode vulnerabilities in the past and they only turned out not to be readily exploitable due to ASLR on modern devices".
Unfortunately that dream never came to light.
http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-2...