Array index error in the dahdi/tor2.c driver in Zaptel (aka DAHDI) 1.4.11 and earlier allows local users in the dialout group to overwrite an integer value in kernel memory by writing to /dev/zap/ctl, related to an incorrect tor2 patch for CVE-2008-5396 that uses the wrong variable in a range check against the value of lc->sync.
https://exchange.xforce.ibmcloud.com/vulnerabilities/47666
https://bugzilla.redhat.com/show_bug.cgi?id=475446#c4
http://svn.digium.com/view/dahdi?view=rev&revision=5590