set_interface_linkmtu(const char *iface, uint32_t mtu)
{
	if (privsep_enabled())
		return privsep_interface_linkmtu(iface, mtu);

	return set_interface_var(iface,
				 PROC_SYS_IP6_LINKMTU, "LinkMTU",
				 mtu);
}

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.