The Linux kernel before 4.8 allows local users to bypass ASLR on setuid programs (such as /bin/su) because install_exec_creds() is called too late in load_elf_binary() in fs/binfmt_elf.c, and thus the ptrace_may_access() check has a race condition when reading /proc/pid/stat.
Exploitability
AV:LAC:HPR:LUI:NScope
S:UImpact
C:HI:NA:N4.7/CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N