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.