The Linux Kernel imposes a size restriction on the arguments and environmental strings passed through RLIMIT_STACK/RLIM_INFINITY (1/4 of the size), but does not take the argument and environment pointers into account, which allows attackers to bypass this limitation. This affects Linux Kernel versions 4.11.5 and earlier. It appears that this feature was introduced in the Linux Kernel version 2.6.23.
This method in itself is not an exploit, but bypassing this mechanism is the flaw/issue being tracked.
Future Linux kernel updates for the respective releases may address this issue.