# CVE-2026-23048: udp: call skb_orphan() before skb_attempt_defer_free()

> A missing skb_orphan call in the Linux kernel UDP receive path can trigger a warning and potential instability, requiring a kernel patch.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Feb 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-23048, DEBIAN-CVE-2026-23048, GHSA-h5xw-xh97-3j7m, UBUNTU-CVE-2026-23048

## What is CVE-2026-23048?

CVE-2026-23048 is a denial of service vulnerability in Linux, published on 4 Feb 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:

udp: call skb_orphan() before skb_attempt_defer_free()

Standard UDP receive path does not use skb->destructor.

But skmsg layer does use it, since it calls skb_set_owner_sk_safe()
from udp_read_skb().

This then triggers this warning in skb_attempt_defer_free():

    DEBUG_NET_WARN_ON_ONCE(skb->destructor);

We must call skb_orphan() to fix this issue.

## Which versions are affected by CVE-2026-23048?


## How do I fix CVE-2026-23048?

Apply the vendor's patch.

## Is CVE-2026-23048 being exploited?

There is no known exploitation of CVE-2026-23048 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23048 and fix it if it is affected.

What it is: CVE-2026-23048 is a denial of service vulnerability in Linux, published on 4 Feb 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-2026-23048 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-2026-23048/ (Markdown: https://insights.sbomify.com/CVE-2026-23048/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23048
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23048
- OSV: https://osv.dev/vulnerability/CVE-2026-23048

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23048/
Summaries are generated and may contain mistakes; the official description above is the record.