drivers/video/msm/mdss/mdss_mdp_util.c in the Qualcomm components in Android before 2016-08-05 on Nexus 5 devices does not verify that a mapping exists before proceeding with an unmap operation, which allows attackers to gain privileges via a crafted application, aka Android internal bug 28815158 and Qualcomm internal bugs CR794217 and CR836226.