CVE-2026-97608

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

netfilter: nf log: unregister loggers before per-net teardown

nf log syslog and nfnetlink log unregister their per-network namespace operations before unregistering their global logger backends. This leaves a window where a sysctl or netlink writer can rebind the still- registered logger after the per-net pre-exit callback cleared the old selection.

The race looks like this:

CPU 0 CPU 1

unregister pernet subsys() nf log unset(net, logger) net->nf.nf loggers[pf] = NULL

                lock nf log mutex
                find logger in loggers[][]
                net->nf.nf loggers[pf] = logger
                unlock nf log mutex

nf log unregister(logger) lock nf log mutex loggers[pf][type] = NULL unlock nf log mutex synchronize rcu() module exit returns module core frees backend memory

Later, a sysctl read or packet logging operation can dereference the stale per-net logger pointer.

Fix this by unregistering the global logger backends before tearing down per-net state. Once the global registrations are gone, later writers can no longer rebind the logger. unregister pernet subsys() already waits for an RCU grace period after the pre-exit callback clears the per-net selection, while nf log unregister() continues to cover readers of the global logger table.

Apply this ordering fix to both nf log backends that combine per-net teardown with global logger registration.