From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-43441: net: bonding: Fix nd_tbl NULL dereference when IPv6 is disabled
Date: Fri, 8 May 2026 16:22:50 +0200 [thread overview]
Message-ID: <2026050854-CVE-2026-43441-72a0@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
net: bonding: Fix nd_tbl NULL dereference when IPv6 is disabled
When booting with the 'ipv6.disable=1' parameter, the nd_tbl is never
initialized because inet6_init() exits before ndisc_init() is called
which initializes it. If bonding ARP/NS validation is enabled, an IPv6
NS/NA packet received on a slave can reach bond_validate_na(), which
calls bond_has_this_ip6(). That path calls ipv6_chk_addr() and can
crash in __ipv6_chk_addr_and_flags().
BUG: kernel NULL pointer dereference, address: 00000000000005d8
Oops: Oops: 0000 [#1] SMP NOPTI
RIP: 0010:__ipv6_chk_addr_and_flags+0x69/0x170
Call Trace:
<IRQ>
ipv6_chk_addr+0x1f/0x30
bond_validate_na+0x12e/0x1d0 [bonding]
? __pfx_bond_handle_frame+0x10/0x10 [bonding]
bond_rcv_validate+0x1a0/0x450 [bonding]
bond_handle_frame+0x5e/0x290 [bonding]
? srso_alias_return_thunk+0x5/0xfbef5
__netif_receive_skb_core.constprop.0+0x3e8/0xe50
? srso_alias_return_thunk+0x5/0xfbef5
? update_cfs_rq_load_avg+0x1a/0x240
? srso_alias_return_thunk+0x5/0xfbef5
? __enqueue_entity+0x5e/0x240
__netif_receive_skb_one_core+0x39/0xa0
process_backlog+0x9c/0x150
__napi_poll+0x30/0x200
? srso_alias_return_thunk+0x5/0xfbef5
net_rx_action+0x338/0x3b0
handle_softirqs+0xc9/0x2a0
do_softirq+0x42/0x60
</IRQ>
<TASK>
__local_bh_enable_ip+0x62/0x70
__dev_queue_xmit+0x2d3/0x1000
? srso_alias_return_thunk+0x5/0xfbef5
? srso_alias_return_thunk+0x5/0xfbef5
? packet_parse_headers+0x10a/0x1a0
packet_sendmsg+0x10da/0x1700
? kick_pool+0x5f/0x140
? srso_alias_return_thunk+0x5/0xfbef5
? __queue_work+0x12d/0x4f0
__sys_sendto+0x1f3/0x220
__x64_sys_sendto+0x24/0x30
do_syscall_64+0x101/0xf80
? exc_page_fault+0x6e/0x170
? srso_alias_return_thunk+0x5/0xfbef5
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
Fix this by checking ipv6_mod_enabled() before dispatching IPv6 packets to
bond_na_rcv(). If IPv6 is disabled, return early from bond_rcv_validate()
and avoid the path to ipv6_chk_addr().
The Linux kernel CVE team has assigned CVE-2026-43441 to this issue.
Affected and fixed versions
===========================
Issue introduced in 5.18 with commit 4e24be018eb9dbcefa4b01c07e298b147dc1a4d7 and fixed in 6.1.167 with commit 49dbfcb70eca5f6f9043594e1e323c74c39e3863
Issue introduced in 5.18 with commit 4e24be018eb9dbcefa4b01c07e298b147dc1a4d7 and fixed in 6.6.130 with commit cf6099ef493b94e140b0fad52482a78853115318
Issue introduced in 5.18 with commit 4e24be018eb9dbcefa4b01c07e298b147dc1a4d7 and fixed in 6.12.78 with commit c78f01abe535853f13f0b26cd5b1d2f19bf52e2f
Issue introduced in 5.18 with commit 4e24be018eb9dbcefa4b01c07e298b147dc1a4d7 and fixed in 6.18.19 with commit 95faa1459b83fa544191e82ccc73856f03b7741f
Issue introduced in 5.18 with commit 4e24be018eb9dbcefa4b01c07e298b147dc1a4d7 and fixed in 6.19.9 with commit c9c238066fb254dabf65e27379f93c56112c5b96
Issue introduced in 5.18 with commit 4e24be018eb9dbcefa4b01c07e298b147dc1a4d7 and fixed in 7.0 with commit 30021e969d48e5819d5ae56936c2f34c0f7ce997
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-2026-43441
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:
drivers/net/bonding/bond_main.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/49dbfcb70eca5f6f9043594e1e323c74c39e3863
https://git.kernel.org/stable/c/cf6099ef493b94e140b0fad52482a78853115318
https://git.kernel.org/stable/c/c78f01abe535853f13f0b26cd5b1d2f19bf52e2f
https://git.kernel.org/stable/c/95faa1459b83fa544191e82ccc73856f03b7741f
https://git.kernel.org/stable/c/c9c238066fb254dabf65e27379f93c56112c5b96
https://git.kernel.org/stable/c/30021e969d48e5819d5ae56936c2f34c0f7ce997
reply other threads:[~2026-05-08 14:25 UTC|newest]
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