The mpi_powm function in lib/mpi/mpi-pow.c in the Linux kernel through 4.8.11 does not ensure that memory is allocated for limb data, which allows local users to cause a denial of service (stack memory corruption and panic) via an add_key system call for an RSA key with a zero exponent.
https://access.redhat.com/errata/RHSA-2017:0931
https://access.redhat.com/errata/RHSA-2017:0932
https://access.redhat.com/errata/RHSA-2017:0933
https://access.redhat.com/errata/RHSA-2018:1854
https://bugzilla.redhat.com/show_bug.cgi?id=1395187
http://seclists.org/fulldisclosure/2016/Nov/76
https://github.com/torvalds/linux/commit/f5527fffff3f002b0a6b376163613b82f69de073