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.