ipv6: fix another slab-out-of-bounds in fib6nhflush_exceptions
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v5.4.136 by commit 830251361425c5be044db4d826aaf304ea3d14c6, it was introduced in version v5.3 by commit f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74. For more details please see the references link.