# CVE-2026-31471: xfrm: iptfs: only publish mode_data after clone setup

> A use-after-free in the Linux kernel's IPTFS xfrm module allows attackers to cause denial of service or potentially execute code via failed clone operations.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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:** 22 Apr 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-31471, DEBIAN-CVE-2026-31471, GHSA-xjfc-f2rj-h2hm, UBUNTU-CVE-2026-31471

## What is CVE-2026-31471?

CVE-2026-31471 is a high-severity use after free vulnerability in Linux kernel, published on 22 Apr 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:

xfrm: iptfs: only publish mode_data after clone setup

iptfs_clone_state() stores x->mode_data before allocating the reorder
window. If that allocation fails, the code frees the cloned state and
returns -ENOMEM, leaving x->mode_data pointing at freed memory.

The xfrm clone unwind later runs destroy_state() through x->mode_data,
so the failed clone path tears down IPTFS state that clone_state()
already freed.

Keep the cloned IPTFS state private until all allocations succeed so
failed clones leave x->mode_data unset. The destroy path already
handles a NULL mode_data pointer.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2026-31471?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31471?

Apply the vendor's patch.

## Is CVE-2026-31471 being exploited?

There is no known exploitation of CVE-2026-31471 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-2026-31471 and fix it if it is affected.

What it is: CVE-2026-31471 is a high-severity use after free vulnerability in Linux kernel, published on 22 Apr 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-2026-31471 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-2026-31471/ (Markdown: https://insights.sbomify.com/CVE-2026-31471/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31471
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31471
- OSV: https://osv.dev/vulnerability/CVE-2026-31471

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31471/
Summaries are generated and may contain mistakes; the official description above is the record.