A use-after-free (UAF) flaw exists in the Linux Kernel within the reassembly of fragmented TIPC messages, specifically in the tipc_buf_append() function. The issue results due to a lack of checks in the error handling cleanup and can trigger a UAF on “struct sk_buff”, which may lead to remote code execution.

Mitigation

The TIPC module is not automatically loaded in default configurations. When required, administrative privileges are required to explicitly load this module.
To determine if the TIPC module is loaded, use the following command:

grep tipc /proc/modules

Look for output similar to the following:
tipc 479232 0 - Live 0xffffffffc1ba5000
ip6_udp_tunnel 16384 1 tipc, Live 0xffffffffc1b9b000
udp_tunnel 32768 1 tipc, Live 0xffffffffc1b8b000

Loading the module can be prevented with the following instructions:

echo "install tipc /bin/true" >> /etc/modprobe.d/disable-tipc.conf

The system will need to be restarted if the module is loaded. In most circumstances, the TIPC kernel module will be unable to be unloaded while any network interfaces are active and the protocol is in use.

If the system requires this module to work correctly, this mitigation may not be suitable.