The diag driver in the Qualcomm components in Android before 2016-08-05 on Nexus 5 devices does not ensure unique identifiers in a DCI client table, which allows attackers to gain privileges via a crafted application, aka Android internal bug 28750155 and Qualcomm internal bug CR590721.
https://source.codeaurora.org/quic/la/kernel/msm/commit/?id=fc787ebd71fa231cc7dd2a0d5f2208da0527096a