CVE-2026-98321: netfilter: nf_nat: unregister and release hooks on error

CVE-2026-98321: netfilter: nf_nat: unregister and release hooks on error

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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

netfilter: nf_nat: unregister and release hooks on error

If nf_hook_entries_insert_raw() fails, the NAT hooks get never released,
resulting in a memleak.

Postpone setting nat_proto_net->nat_hook_ops when the hooks are
registered to simplify the error path to decide whether the nat hooks
need unwinding.

The Linux kernel CVE team has assigned CVE-2026-98321 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 4.18 with commit 1cd472bf036ca038e783ef5f058f54e45b7e8180 and fixed in 6.18.54 with commit 79084567cd082fb4482e1ea457580e7d6504dd99
	Issue introduced in 4.18 with commit 1cd472bf036ca038e783ef5f058f54e45b7e8180 and fixed in 7.2.8 with commit df80342f4bfc023ad7d6703df5e27f583ff0cb8d
	Issue introduced in 4.18 with commit 1cd472bf036ca038e783ef5f058f54e45b7e8180 and fixed in 7.3-rc4 with commit cbdd39ce42530a193c56beb206a3356cb6d01016

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-98321
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/netfilter/nf_nat_core.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/79084567cd082fb4482e1ea457580e7d6504dd99
	https://git.kernel.org/stable/c/df80342f4bfc023ad7d6703df5e27f583ff0cb8d
	https://git.kernel.org/stable/c/cbdd39ce42530a193c56beb206a3356cb6d01016