The tcpmss_mangle_packet function in net/netfilter/xt_TCPMSS.c in the Linux kernel before 4.11, and 4.9.x before 4.9.36, allows remote attackers to cause a denial of service (use-after-free and memory corruption) or possibly have unspecified other impact by leveraging the presence of xt_TCPMSS in an iptables action.
https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.36
https://www.debian.org/security/2018/dsa-4187
https://www.arista.com/en/support/advisories-notices/security-advisories/4577-security-advisory-34
https://usn.ubuntu.com/3583-2/
https://usn.ubuntu.com/3583-1/
https://support.f5.com/csp/article/K18352029
https://lkml.org/lkml/2017/4/2/13
https://lists.debian.org/debian-lts-announce/2018/05/msg00000.html
https://github.com/torvalds/linux/commit/2638fd0f92d4397884fd991d8f4925cb3f081901
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1739765
https://access.redhat.com/errata/RHSA-2018:1737
https://access.redhat.com/errata/RHSA-2018:1319
https://access.redhat.com/errata/RHSA-2018:1170
https://access.redhat.com/errata/RHSA-2018:1130
https://access.redhat.com/errata/RHSA-2018:1062
https://access.redhat.com/errata/RHSA-2018:0676
http://www.ubuntu.com/usn/USN-3583-2
http://www.ubuntu.com/usn/USN-3583-1
http://patchwork.ozlabs.org/patch/746618/
http://lists.opensuse.org/opensuse-security-announce/2018-04/msg00014.html
http://lists.opensuse.org/opensuse-security-announce/2018-03/msg00072.html
http://lists.opensuse.org/opensuse-security-announce/2018-03/msg00070.html
http://lists.opensuse.org/opensuse-security-announce/2018-03/msg00067.html
http://lists.opensuse.org/opensuse-security-announce/2018-03/msg00030.html
http://lists.opensuse.org/opensuse-security-announce/2018-02/msg00047.html
http://lists.opensuse.org/opensuse-security-announce/2018-02/msg00038.html
http://lists.opensuse.org/opensuse-security-announce/2018-02/msg00015.html
http://lists.opensuse.org/opensuse-security-announce/2018-02/msg00013.html
http://lists.opensuse.org/opensuse-security-announce/2018-02/msg00008.html