CVE-2026-74565: netfilter: nf_tables: make nft_object rhltable per table

From: Greg Kroah-Hartman <[email protected]>

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

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

netfilter: nf_tables: make nft_object rhltable per table

The nft_object rhltable is global, this allows for accessing objects
that are being dismangled from lookup path by other existing netns.
Given the nft_obj_destroy() releases the object inmediately, this might
lead to use-after-free of these objects that are being released.
Make the existing rhltable per table to address this issue to deal with
with the nft_rcv_nl_event() path too.

Update nft_obj_lookup() to take the table as non-const, otherwise,
compiler complains when passing the objname_ht to rhltable_lookup().

The Linux kernel CVE team has assigned CVE-2026-74565 to this issue.


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

	Issue introduced in 5.1 with commit 4d44175aa5bb5f68772b1eb0306554812294ca52 and fixed in 6.12.103 with commit 1948e4f85b855618b5b9a27265f98d816f4cb7cb
	Issue introduced in 5.1 with commit 4d44175aa5bb5f68772b1eb0306554812294ca52 and fixed in 6.18.44 with commit 63ba12b664a2cd3220ed43e22c717715f4cc2ae8
	Issue introduced in 5.1 with commit 4d44175aa5bb5f68772b1eb0306554812294ca52 and fixed in 7.1.8 with commit 7d4789b58761d9d48d9b5f5e7e0a510c3bbfb3af
	Issue introduced in 5.1 with commit 4d44175aa5bb5f68772b1eb0306554812294ca52 and fixed in 7.2-rc6 with commit f4f699790590bd0896c48a71e9232a65198f92f0

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-2026-74565
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:
	include/net/netfilter/nf_tables.h
	net/netfilter/nf_tables_api.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/1948e4f85b855618b5b9a27265f98d816f4cb7cb
	https://git.kernel.org/stable/c/63ba12b664a2cd3220ed43e22c717715f4cc2ae8
	https://git.kernel.org/stable/c/7d4789b58761d9d48d9b5f5e7e0a510c3bbfb3af
	https://git.kernel.org/stable/c/f4f699790590bd0896c48a71e9232a65198f92f0