linux-cve-announce - CVE-2023-53987: ping: Fix potentail NULL deref for /proc/net/icmp.

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Message-ID: <2025122422-CVE-2023-53987-9f08@gregkh>
Date: Wed, 24 Dec 2025 11:56:31 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53987: ping: Fix potentail NULL deref for /proc/net/icmp.

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

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

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

ping: Fix potentail NULL deref for /proc/net/icmp.

After commit dbca1596bbb0 ("ping: convert to RCU lookups, get rid
of rwlock"), we use RCU for ping sockets, but we should use spinlock
for /proc/net/icmp to avoid a potential NULL deref mentioned in
the previous patch.

Let's go back to using spinlock there.

Note we can convert ping sockets to use hlist instead of hlist_nulls
because we do not use SLAB_TYPESAFE_BY_RCU for ping sockets.

The Linux kernel CVE team has assigned CVE-2023-53987 to this issue.

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

	Issue introduced in 6.0 with commit dbca1596bbb08318f5e3b3b99f8ca0a0d3830a65 and fixed in 6.1.24 with commit 5a08a32e624908890aa0a2eb442bb6a7669891a8
	Issue introduced in 6.0 with commit dbca1596bbb08318f5e3b3b99f8ca0a0d3830a65 and fixed in 6.2.11 with commit 176cbb6da28f36506cc60a4bec4ab8df0c16713a
	Issue introduced in 6.0 with commit dbca1596bbb08318f5e3b3b99f8ca0a0d3830a65 and fixed in 6.3 with commit ab5fb73ffa01072b4d8031cc05801fa1cb653bee
	Issue introduced in 5.19.2 with commit de3d723a3985f282a8c9e468d1e198616eb291c8

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-2023-53987
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/ping.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/5a08a32e624908890aa0a2eb442bb6a7669891a8
	https://git.kernel.org/stable/c/176cbb6da28f36506cc60a4bec4ab8df0c16713a
	https://git.kernel.org/stable/c/ab5fb73ffa01072b4d8031cc05801fa1cb653bee