CVE-2014-4943 is a flaw in the Linux kernel allowing an unprivileged user
to escalate to kernel privilege when CONFIG_PPPOL2TP is enabled. If built
as a module, a work-around to limit this to just the root user would be
to add this to /etc/modprobe.conf:
alias pppox-proto-1 off
blacklist l2tp_ppp
Upstream commit:
https://git.kernel.org/linus/3cf521f7dc87c031617fd47e4b7aa2593c2f3daf
-Kees
– Kees Cook @outflux.net