# CVE-2026-23293: net: vxlan: fix nd_tbl NULL dereference when IPv6 is disabled

> A local attacker can cause a kernel crash by injecting IPv6 packets into a VXLAN interface when IPv6 is disabled via boot parameter.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Mar 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-80723, BELL-CVE-2026-23293, DEBIAN-CVE-2026-23293, GHSA-4mrh-9qq5-26w5, ROOT-OS-DEBIAN-11-CVE-2026-23293, ROOT-OS-DEBIAN-12-CVE-2026-23293, ROOT-OS-DEBIAN-13-CVE-2026-23293, ROOT-OS-UBUNTU-2204-CVE-2026-23293, ROOT-OS-UBUNTU-2404-CVE-2026-23293, UBUNTU-CVE-2026-23293

## What is CVE-2026-23293?

CVE-2026-23293 is a medium-severity vulnerability in Linux kernel, published on 25 Mar 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:

net: vxlan: 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 an IPv6 packet is injected into the interface,
route_shortcircuit() is called and a NULL pointer dereference happens on
neigh_lookup().

 BUG: kernel NULL pointer dereference, address: 0000000000000380
 Oops: Oops: 0000 [#1] SMP NOPTI
 [...]
 RIP: 0010:neigh_lookup+0x20/0x270
 [...]
 Call Trace:
  <TASK>
  vxlan_xmit+0x638/0x1ef0 [vxlan]
  dev_hard_start_xmit+0x9e/0x2e0
  __dev_queue_xmit+0xbee/0x14e0
  packet_sendmsg+0x116f/0x1930
  __sys_sendto+0x1f5/0x200
  __x64_sys_sendto+0x24/0x30
  do_syscall_64+0x12f/0x1590
  entry_SYSCALL_64_after_hwframe+0x76/0x7e

Fix this by adding an early check on route_shortcircuit() when protocol
is ETH_P_IPV6. Note that ipv6_mod_enabled() cannot be used here because
VXLAN can be built-in even when IPv6 is built as a module.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-23293?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23293?

Apply the vendor's patch.

## Is CVE-2026-23293 being exploited?

There is no known exploitation of CVE-2026-23293 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-2026-23293 and fix it if it is affected.

What it is: CVE-2026-23293 is a medium-severity vulnerability in Linux kernel, published on 25 Mar 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-2026-23293 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-2026-23293/ (Markdown: https://insights.sbomify.com/CVE-2026-23293/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23293
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23293
- OSV: https://osv.dev/vulnerability/CVE-2026-23293

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23293/
Summaries are generated and may contain mistakes; the official description above is the record.