CVE-2026-43441 net: bonding: Fix nd_tbl NULL dereference when IPv6 is disabled
A remote attacker can cause a kernel crash via IPv6 packets if bonding validation is enabled and IPv6 is disabled at boot.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-43441?
CVE-2026-43441 is a high-severity vulnerability in Linux kernel, published on 8 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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().
Weakness: CWE-476
Which versions are affected by CVE-2026-43441?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43441?
Apply the vendor's patch.
Is CVE-2026-43441 being exploited?
There is no known exploitation of CVE-2026-43441 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43441, DEBIAN-CVE-2026-43441, GHSA-pfqp-2whq-57g2, ROOT-OS-UBUNTU-2404-CVE-2026-43441, UBUNTU-CVE-2026-43441.