CVE-2026-98624: netfilter: nfnetlink_queue: hold nfnl mutex in event notifier

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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

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

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

netfilter: nfnetlink_queue: hold nfnl mutex in event notifier

We must serialize the release notifier and the config netlink function.
A concurrent thread can issue close() which can call the release function
while unrelated socket processes UNBIND request for same portid:

Oops: general protection fault, [..]
RIP: 0010:__instance_destroy+0x60/0x210 [nfnetlink_queue]
Call Trace:
 nfqnl_recv_config+0x9b0/0xdc0 [nfnetlink_queue]
 nfnetlink_rcv_msg+0x7c2/0xeb0
 ? __pfx_nfnetlink_rcv_msg+0x10/0x10

After this, parallel UNBIND and URELEASE events are impossible.

This change isn't nice, but its the shortest fix given instances
are not refcounted and the nfnetlink config callback drops the
rcu read lock early due to need for sleeping allocations.

The Linux kernel CVE team has assigned CVE-2026-98624 to this issue.


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

	Issue introduced in 2.6.14 with commit 7af4cc3fa158ff1dda6e7451c7e6afa6b0bb85cb and fixed in 5.10.271 with commit 46432f2e76f7c385d82506304a2928e7d293289f
	Issue introduced in 2.6.14 with commit 7af4cc3fa158ff1dda6e7451c7e6afa6b0bb85cb and fixed in 5.15.222 with commit 597320337c3da06c92a9e95cfc755da66fedc476
	Issue introduced in 2.6.14 with commit 7af4cc3fa158ff1dda6e7451c7e6afa6b0bb85cb and fixed in 6.1.189 with commit 2e9be1302f25c9be51c2fb8c907bc6d8a1050e33
	Issue introduced in 2.6.14 with commit 7af4cc3fa158ff1dda6e7451c7e6afa6b0bb85cb and fixed in 6.6.158 with commit d559e06a5ab7c064100aafd5c826eadd0f1c6216
	Issue introduced in 2.6.14 with commit 7af4cc3fa158ff1dda6e7451c7e6afa6b0bb85cb and fixed in 6.12.112 with commit 1d1184411599a7c2217560bab3bbe641c6d03b95
	Issue introduced in 2.6.14 with commit 7af4cc3fa158ff1dda6e7451c7e6afa6b0bb85cb and fixed in 6.18.55 with commit 07a3ec8fdc5a1267c00cd6fd1cf8bbb5cda913c1
	Issue introduced in 2.6.14 with commit 7af4cc3fa158ff1dda6e7451c7e6afa6b0bb85cb and fixed in 7.2.9 with commit 8137a39e08e838ced234044384740ceeb99ed388
	Issue introduced in 2.6.14 with commit 7af4cc3fa158ff1dda6e7451c7e6afa6b0bb85cb and fixed in 7.3-rc5 with commit 9461613afc59acef44a0071b0dd5075f6e993ffe

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-2026-98624
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/nfnetlink_queue.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/46432f2e76f7c385d82506304a2928e7d293289f
	https://git.kernel.org/stable/c/597320337c3da06c92a9e95cfc755da66fedc476
	https://git.kernel.org/stable/c/2e9be1302f25c9be51c2fb8c907bc6d8a1050e33
	https://git.kernel.org/stable/c/d559e06a5ab7c064100aafd5c826eadd0f1c6216
	https://git.kernel.org/stable/c/1d1184411599a7c2217560bab3bbe641c6d03b95
	https://git.kernel.org/stable/c/07a3ec8fdc5a1267c00cd6fd1cf8bbb5cda913c1
	https://git.kernel.org/stable/c/8137a39e08e838ced234044384740ceeb99ed388
	https://git.kernel.org/stable/c/9461613afc59acef44a0071b0dd5075f6e993ffe