In the Linux kernel, the following vulnerability has been resolved:

net: do not delay dst_entries_add() in dst_release()

dst_entries_add() uses per-cpu data that might be freed at netns
dismantle from ip6_route_net_exit() calling dst_entries_destroy()

Before ip6_route_net_exit() can be called, we release all
the dsts associated with this netns, via calls to dst_release(),
which waits an rcu grace period before calling dst_destroy()

dst_entries_add() use in dst_destroy() is racy, because
dst_entries_destroy() could have been called already.

Decrementing the number of dsts must happen sooner.

Notes:

1) in CONFIG_XFRM case, dst_destroy() can call
   dst_release_immediate(child), this might also cause UAF
   if the child does not have DST_NOCOUNT set.
   IPSEC maintainers might take a look and see how to address this.

2) There is also discussion about removing this count of dst,
   which might happen in future kernels.

kernel.org https://git.kernel.org/stable/c/3c7c918ec0aa3555372c5a57f18780b7a96c5cfc [No types assigned]

kernel.org https://git.kernel.org/stable/c/ac888d58869bb99753e7652be19a151df9ecb35d [No types assigned]

kernel.org https://git.kernel.org/stable/c/eae7435b48ffc8e9be0ff9cfeae40af479a609dd [No types assigned]