# CVE-2026-80664: netfilter: xt_nat: reject unsupported target families

> A NULL pointer dereference in the Linux kernel netfilter NAT module allows local attackers to cause a system crash via bridge-family rules.

- **Severity:** High 7.3 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/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:** 28 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-80664, DEBIAN-CVE-2026-80664, GHSA-4wgj-9qhp-2583, UBUNTU-CVE-2026-80664

## What is CVE-2026-80664?

CVE-2026-80664 is a high-severity vulnerability in Linux, published on 28 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:

netfilter: xt_nat: reject unsupported target families

xt_nat SNAT and DNAT target handlers assume IP-family conntrack state
is present and can dereference a NULL pointer when instantiated from an
unsupported family through nft_compat. A bridge-family compat rule can
therefore trigger a NULL-dereference in nf_nat_setup_info().

Reject non-IP families in xt_nat_checkentry() so unsupported targets
cannot be installed. Keep NFPROTO_INET allowed for valid inet NAT
compat users and leave the runtime fast path unchanged.

[ The crash was fixed via
  9dbba7e694ec ("netfilter: nft_compat: ebtables emulation must reject non-bridge targets"),
  so this patch is no longer critical.
  Nevertheless, NAT is only relevant for ipv4/ipv6, so this extra
  family check is a good idea in any case. ]

## Which versions are affected by CVE-2026-80664?


## How do I fix CVE-2026-80664?

Apply the vendor's patch.

## Is CVE-2026-80664 being exploited?

There is no known exploitation of CVE-2026-80664 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80664 and fix it if it is affected.

What it is: CVE-2026-80664 is a high-severity vulnerability in Linux, published on 28 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-2026-80664 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-2026-80664/ (Markdown: https://insights.sbomify.com/CVE-2026-80664/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80664
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80664
- OSV: https://osv.dev/vulnerability/CVE-2026-80664

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80664/
Summaries are generated and may contain mistakes; the official description above is the record.