The snd_ctl_elem_add function in sound/core/control.c in the ALSA control implementation in the Linux kernel before 3.15.2 does not check authorization for SNDRV_CTL_IOCTL_ELEM_REPLACE commands, which allows local users to remove kernel controls and cause a denial of service (use-after-free and system crash) by leveraging /dev/snd/controlCX access for an ioctl call.
git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=82262a46627bebb0febcc26664746c25cef08563
lists.opensuse.org/opensuse-security-announce/2015-04/msg00020.html
rhn.redhat.com/errata/RHSA-2014-1083.html
secunia.com/advisories/59434
secunia.com/advisories/59777
secunia.com/advisories/60545
secunia.com/advisories/60564
www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.15.2
www.openwall.com/lists/oss-security/2014/06/26/6
www.securityfocus.com/bid/68162
www.ubuntu.com/usn/USN-2334-1
www.ubuntu.com/usn/USN-2335-1
bugzilla.redhat.com/show_bug.cgi?id=1113445
github.com/torvalds/linux/commit/82262a46627bebb0febcc26664746c25cef08563