linux-cve-announce - CVE-2023-53200: netfilter: x_tables: fix percpu counter block leak on error path when creating new netns

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Message-ID: <2025091509-CVE-2023-53200-a0c8@gregkh>
Date: Mon, 15 Sep 2025 16:21:34 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53200: netfilter: x_tables: fix percpu counter block leak on error path when creating new netns

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

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

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

netfilter: x_tables: fix percpu counter block leak on error path when creating new netns

Here is the stack where we allocate percpu counter block:

  +-< __alloc_percpu
    +-< xt_percpu_counter_alloc
      +-< find_check_entry # {arp,ip,ip6}_tables.c
        +-< translate_table

And it can be leaked on this code path:

  +-> ip6t_register_table
    +-> translate_table # allocates percpu counter block
    +-> xt_register_table # fails

there is no freeing of the counter block on xt_register_table fail.
Note: xt_percpu_counter_free should be called to free it like we do in
do_replace through cleanup_entry helper (or in __ip6t_unregister_table).

Probability of hitting this error path is low AFAICS (xt_register_table
can only return ENOMEM here, as it is not replacing anything, as we are
creating new netns, and it is hard to imagine that all previous
allocations succeeded and after that one in xt_register_table failed).
But it's worth fixing even the rare leak.

The Linux kernel CVE team has assigned CVE-2023-53200 to this issue.


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

	Issue introduced in 4.2 with commit 71ae0dff02d756e4d2ca710b79f2ff5390029a5f and fixed in 5.15.100 with commit e306dbee4c98025a9326386023a12ef4d887e9d1
	Issue introduced in 4.2 with commit 71ae0dff02d756e4d2ca710b79f2ff5390029a5f and fixed in 6.1.18 with commit 512b6c4b83c91d007301ea7d7f095d16c3aceacd
	Issue introduced in 4.2 with commit 71ae0dff02d756e4d2ca710b79f2ff5390029a5f and fixed in 6.2.5 with commit 3cc9610a87b7dde82f7360dd4eb6c2c27940ed57
	Issue introduced in 4.2 with commit 71ae0dff02d756e4d2ca710b79f2ff5390029a5f and fixed in 6.3 with commit 0af8c09c896810879387decfba8c942994bb61f5

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-2023-53200
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/ipv4/netfilter/arp_tables.c
	net/ipv4/netfilter/ip_tables.c
	net/ipv6/netfilter/ip6_tables.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/e306dbee4c98025a9326386023a12ef4d887e9d1
	https://git.kernel.org/stable/c/512b6c4b83c91d007301ea7d7f095d16c3aceacd
	https://git.kernel.org/stable/c/3cc9610a87b7dde82f7360dd4eb6c2c27940ed57
	https://git.kernel.org/stable/c/0af8c09c896810879387decfba8c942994bb61f5