# 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.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 May 2026
- **Updated:** 19 Oct 2026
- **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

## 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 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-43441?

It affects 1 product.


Products: 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

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43441 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-43441 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-43441/ (Markdown: https://insights.sbomify.com/CVE-2026-43441/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43441
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43441
- OSV: https://osv.dev/vulnerability/CVE-2026-43441

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43441/
Summaries are generated and may contain mistakes; the official description above is the record.