Linux kernel is vulnerable to denial of service(DoS) attacks. This occurs in implementation of associative arrays where the add_key systemcall and KEYCTL_UPDATE operations allowed for a NULL payload with a nonzero length. When accessing the payload within this length parameters value, an unprivileged user could trivially cause a NULL pointer dereference.
git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=5649645d725c73df4302428ee4e02c869248b4c5
www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.11.5
www.securityfocus.com/bid/101292
access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/7.5_Release_Notes/index.html
access.redhat.com/errata/RHSA-2018:0676
access.redhat.com/security/cve/CVE-2017-13305
access.redhat.com/security/cve/CVE-2017-15274
access.redhat.com/security/updates/classification/#important
bugzilla.redhat.com/show_bug.cgi?id=1292927
bugzilla.redhat.com/show_bug.cgi?id=1401061
bugzilla.redhat.com/show_bug.cgi?id=1430418
bugzilla.redhat.com/show_bug.cgi?id=1448770
bugzilla.redhat.com/show_bug.cgi?id=1452589
bugzilla.redhat.com/show_bug.cgi?id=1462329
bugzilla.redhat.com/show_bug.cgi?id=1500894
bugzilla.redhat.com/show_bug.cgi?id=1503749
bugzilla.redhat.com/show_bug.cgi?id=1506255
bugzilla.redhat.com/show_bug.cgi?id=1507270
bugzilla.redhat.com/show_bug.cgi?id=1509264
bugzilla.redhat.com/show_bug.cgi?id=1518274
bugzilla.redhat.com/show_bug.cgi?id=1518638
bugzilla.suse.com/show_bug.cgi?id=1045327
github.com/torvalds/linux/commit/5649645d725c73df4302428ee4e02c869248b4c5
patchwork.kernel.org/patch/9781573/
usn.ubuntu.com/3583-1/
usn.ubuntu.com/3583-2/