An issue was discovered in net/ipv6/ip6mr.c in the Linux kernel before 4.11. By setting a specific socket option, an attacker can control a pointer in kernel land and cause an inet_csk_listen_stop general protection fault, or potentially execute arbitrary code under certain circumstances. The issue can be triggered as root (e.g., inside a default LXC container or with the CAP_NET_ADMIN capability) or after namespace unsharing. This occurs because sk_type and protocol are not checked in the appropriate part of the ip6_mroute_* functions. NOTE: this affects Linux distributions that use 4.9.x longterm kernels before 4.9.187.
https://github.com/torvalds/linux/commit/99253eb750fda6a644d5188fb26c43bad8d5a745
https://lists.debian.org/debian-lts-announce/2019/08/msg00016.html
https://lists.debian.org/debian-lts-announce/2019/08/msg00017.html
https://salsa.debian.org/kernel-team/linux/commit/baefcdc2f29923e7325ce4e1a72c3ff0a9800f32
https://seclists.org/bugtraq/2019/Aug/26
https://support.f5.com/csp/article/K41582535
https://support.f5.com/csp/article/K41582535?utm_source=f5support&%3Butm_medium=RSS