The slhc_init function in drivers/net/slip/slhc.c in the Linux kernel through 4.2.3 does not ensure that certain slot numbers are valid, which allows local users to cause a denial of service (NULL pointer dereference and system crash) via a crafted PPPIOCSMAXCID ioctl call.<a href=http://cwe.mitre.org/data/definitions/476.html>CWE-476: NULL Pointer Dereference</a> http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-7799