Linux Kernel Ping_Unhash Function Vulnerability (CVE-2015-3636)

This vulnerability involves the ping_unhash function in net/ipv4/ping.c in the Linux kernel before 4.0.3, where it does not initialize a certain list data structure during an unhash operation. This allows attackers to gain privileges or cause a denial of service (use-after-free and system crash) by leveraging the ability to make a SOCK_DGRAM socket system call for the IPPROTO_ICMP or IPPROTO_ICMPV6 protocol, and then making a connect system call after a disconnect.