# CVE-2026-98370: xfrm: fix compat ALLOCSPI request use-after-free

> A use-after-free in the Linux kernel xfrm subsystem allows local attackers to execute arbitrary code or escalate privileges via crafted netlink messages.

- **Severity:** Not scored
- **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:** 6 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-106011, BELL-CVE-2026-98370, DEBIAN-CVE-2026-98370, GHSA-xf8r-gcp9-vg22, UBUNTU-CVE-2026-98370

## What is CVE-2026-98370?

CVE-2026-98370 is an use after free vulnerability in Linux, published on 6 Oct 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: fix compat ALLOCSPI request use-after-free

xfrm_state_netlink() builds the ALLOCSPI response with
dump_one_state(), which already calls alloc_compat() with the response
skb and header.

xfrm_alloc_userspi() then calls alloc_compat() again, but passes the
original request skb and its header. For a compat request, the
translator therefore interprets the 228-byte compat xfrm_userspi_info
as the 232-byte native layout and reads four bytes past the declared
payload. It also publishes the translated child through the request's
frag_list.

A multicast clone of the request shares skb_shared_info and can observe
that child. xfrm_user_rcv_msg() frees it after the request handler
returns, racing a compat receiver which may still be copying from it and
resulting in a use-after-free.

Remove the redundant conversion. The response keeps its correct compat
translation from dump_one_state(), and no child is attached to the
inbound request.

## Which versions are affected by CVE-2026-98370?


## How do I fix CVE-2026-98370?

Apply the vendor's patch.

## Is CVE-2026-98370 being exploited?

There is no known exploitation of CVE-2026-98370 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98370 and fix it if it is affected.

What it is: CVE-2026-98370 is an use after free vulnerability in Linux, published on 6 Oct 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-2026-98370 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-2026-98370/ (Markdown: https://insights.sbomify.com/CVE-2026-98370/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98370
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98370
- OSV: https://osv.dev/vulnerability/CVE-2026-98370

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98370/
Summaries are generated and may contain mistakes; the official description above is the record.