# CVE-2026-98793: netfilter: bpf: reject invalid NAT manipulation types

> A missing validation in the Linux kernel netfilter BPF NAT handling allows a low-privileged user to trigger a kernel warning and potential crash, causing denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-109290, BELL-CVE-2026-98793, DEBIAN-CVE-2026-98793, GHSA-g33v-6845-q9px, UBUNTU-CVE-2026-98793

## What is CVE-2026-98793?

CVE-2026-98793 is a denial of service vulnerability in Linux, published on 18 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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

netfilter: bpf: reject invalid NAT manipulation types

As bpf_ct_set_nat_info() is not validating the NAT manipulation type a
wrong value can be passed directly to nf_nat_setup_info(). This triggers
the WARN_ON() at nf_nat_setup_info() and if panic_on_warn isn't set,
then IPS_SRC_NAT_DONE is set without adding nat_bysource and conntrack
cleanup tries to unlink an uninitialized hlist node.

Fix this by checking that NAT manipulation type is correct before
calling nf_nat_setup_info(). In addition, if the WARN_ON is hit, return
NF_DROP instead of continuing with the processing to avoid similar
situations in the future.

## Which versions are affected by CVE-2026-98793?


## How do I fix CVE-2026-98793?

Apply the vendor's patch.

## Is CVE-2026-98793 being exploited?

There is no known exploitation of CVE-2026-98793 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98793 and fix it if it is affected.

What it is: CVE-2026-98793 is a denial of service vulnerability in Linux, published on 18 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-98793 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-2026-98793/ (Markdown: https://insights.sbomify.com/CVE-2026-98793/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98793
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98793
- OSV: https://osv.dev/vulnerability/CVE-2026-98793

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98793/
Summaries are generated and may contain mistakes; the official description above is the record.