# CVE-2026-43452: netfilter: x_tables: guard option walkers against 1-byte tail reads

> A missing bounds check in Linux kernel netfilter option walkers allows out-of-bounds reads, potentially causing crashes or information leaks.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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-2026-43452, DEBIAN-CVE-2026-43452, GHSA-3jfw-v6mf-ccwx, ROOT-OS-DEBIAN-11-CVE-2026-43452, ROOT-OS-UBUNTU-2204-CVE-2026-43452, ROOT-OS-UBUNTU-2404-CVE-2026-43452, UBUNTU-CVE-2026-43452

## What is CVE-2026-43452?

CVE-2026-43452 is a high-severity memory corruption 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:

netfilter: x_tables: guard option walkers against 1-byte tail reads

When the last byte of options is a non-single-byte option kind, walkers
that advance with i += op[i + 1] ? : 1 can read op[i + 1] past the end
of the option area.

Add an explicit i == optlen - 1 check before dereferencing op[i + 1]
in xt_tcpudp and xt_dccp option walkers.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-43452?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43452?

Apply the vendor's patch.

## Is CVE-2026-43452 being exploited?

There is no known exploitation of CVE-2026-43452 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-2026-43452 and fix it if it is affected.

What it is: CVE-2026-43452 is a high-severity memory corruption 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-2026-43452 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-2026-43452/ (Markdown: https://insights.sbomify.com/CVE-2026-43452/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43452
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43452
- OSV: https://osv.dev/vulnerability/CVE-2026-43452

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43452/
Summaries are generated and may contain mistakes; the official description above is the record.