# CVE-2026-68336: bonding: fix devconf_all NULL dereference when IPv6 is disabled

> A NULL pointer dereference in the Linux kernel bonding driver causes a system crash when IPv6 is disabled, leading to denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** BELL-CVE-2026-68336, DEBIAN-CVE-2026-68336, GHSA-gmpf-gmwm-hxhp, UBUNTU-CVE-2026-68336

## What is CVE-2026-68336?

CVE-2026-68336 is a vulnerability in Linux, published on 10 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

bonding: fix devconf_all NULL dereference when IPv6 is disabled

When booting with the 'ipv6.disable=1' parameter, the devconf_all is
never initialized because inet6_init() exits before addrconf_init() is
called which initializes it. bond_send_validate(), however, will still
call bond_ns_send_all() even ipv6 is indeed disabled. It will lead to
NULL derefence of net->ipv6.devconf_all in ip6_pol_route().

 BUG: kernel NULL pointer dereference, address: 000000000000000c
 [...]
 Workqueue: bond0 bond_arp_monitor [bonding]
 RIP: 0010:ip6_pol_route+0x69/0x480
 [...]
 Call Trace:
  <TASK>
  ? srso_return_thunk+0x5/0x5f
  ? __pfx_ip6_pol_route_output+0x10/0x10
  fib6_rule_lookup+0xfe/0x260
  ? wakeup_preempt+0x8a/0x90
  ? srso_return_thunk+0x5/0x5f
  ? srso_return_thunk+0x5/0x5f
  ? sched_balance_rq+0x369/0x810
  ip6_route_output_flags+0xd7/0x170
  bond_ns_send_all+0xde/0x280 [bonding]
  bond_ab_arp_probe+0x296/0x320 [bonding]
  ? srso_return_thunk+0x5/0x5f
  bond_activebackup_arp_mon+0xb4/0x2c0 [bonding]
  process_one_work+0x196/0x370
  worker_thread+0x1af/0x320
  ? srso_return_thunk+0x5/0x5f
  ? __pfx_worker_thread+0x10/0x10
  kthread+0xe3/0x120
  ? __pfx_kthread+0x10/0x10
  ret_from_fork+0x199/0x260
  ? __pfx_kthread+0x10/0x10
  ret_from_fork_asm+0x1a/0x30
  </TASK>

Fix this by adding ipv6_mod_enabled() condition check in the caller.

## Which versions are affected by CVE-2026-68336?


## How do I fix CVE-2026-68336?

Apply the vendor's patch.

## Is CVE-2026-68336 being exploited?

There is no known exploitation of CVE-2026-68336 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68336 and fix it if it is affected.

What it is: CVE-2026-68336 is a vulnerability in Linux, published on 10 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-68336 in the wild and no public exploit code.

Affected product: Linux. 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-2026-68336/ (Markdown: https://insights.sbomify.com/CVE-2026-68336/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68336
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68336
- OSV: https://osv.dev/vulnerability/CVE-2026-68336

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68336/
Summaries are generated and may contain mistakes; the official description above is the record.