The Framework UI permission-dialog implementation in Android 6.x before 2016-06-01 allows attackers to conduct tapjacking attacks and access arbitrary private-storage files by creating a partially overlapping window, aka internal bug 26677796.
android.googlesource.com/platform/frameworks/base/+/613f63b938145bb86cd64fe0752eaf5e99b5f628
android.googlesource.com/platform/frameworks/native/+/03a53d1c7765eeb3af0bc34c3dff02ada1953fbf
android.googlesource.com/platform/packages/apps/PackageInstaller/+/2068c7997265011ddc5e4dfa3418407881f7f81e
source.android.com/security/bulletin/2016-06-01.html