The BnGraphicBufferConsumer::onTransact function in libs/gui/IGraphicBufferConsumer.cpp in mediaserver in Android 5.x before 5.1.1 LMY49H and 6.x before 2016-03-01 does not initialize a certain slot variable, which allows attackers to obtain sensitive information, and consequently bypass an unspecified protection mechanism, by triggering an ATTACH_BUFFER action, as demonstrated by obtaining Signature or SignatureOrSystem access, aka internal bug 26338113.
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.