A vulnerability was found in base_sock_create in drivers/isdn/mISDN/socket.c in the AF_ISDN network module in the Linux kernel does not enforce CAP_NET_RAW, which means that unprivileged users can create a raw socket.
Created kernel tracking bugs for this issue:
Affects: fedora-all [bug 1758249]
kernel-5.3.6-100.fc29, kernel-headers-5.3.6-100.fc29, kernel-tools-5.3.6-100.fc29 has been pushed to the Fedora 29 stable repository. If problems still persist, please make note of it in this bug report.
It -may- be possible that a local user can use this to directly control attached ISDN hardware, hanging up the connection or redialing long distance/high fee numbers incurring large fees to the telephony systems.
At this time the only known way to 'mitigate' this flaw is to blacklist the kernel module from being loaded. Creating raw sockets with this protocol is a method of communicating with ISDN hardware, a technology that is becoming less and less common.
Check https://access.redhat.com/solutions/41278 for instructions on how to disable the mISDN_core.ko module.