# CVE-2026-98383: bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL

> A use-after-free vulnerability in the Linux kernel BPF subsystem allows local attackers with high privileges to execute arbitrary code or escalate privileges.

- **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:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Oct 2026
- **Updated:** 24 Oct 2026
- **Also known as:** AZL-106899, BELL-CVE-2026-98383, DEBIAN-CVE-2026-98383, GHSA-ph4x-4wh2-2qrm, UBUNTU-CVE-2026-98383

## What is CVE-2026-98383?

CVE-2026-98383 is a high-severity use after free vulnerability in Linux, published on 9 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:

bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL

An LWT_SEG6LOCAL program can invalidate its cached SRH with
bpf_lwt_seg6_adjust_srh() and then call bpf_skb_pull_data(). The latter
may reallocate skb->head, leaving the per-CPU SRH pointer dangling.
Post-program SRH validation then writes through that pointer.

Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL programs so the verifier
rejects this unsafe helper combination. Other LWT program types continue
to expose the helper through lwt_out_func_proto().

## Which versions are affected by CVE-2026-98383?


## How do I fix CVE-2026-98383?

Apply the vendor's patch.

## Is CVE-2026-98383 being exploited?

There is no known exploitation of CVE-2026-98383 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98383 and fix it if it is affected.

What it is: CVE-2026-98383 is a high-severity use after free vulnerability in Linux, published on 9 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-2026-98383 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-2026-98383/ (Markdown: https://insights.sbomify.com/CVE-2026-98383/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98383
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98383
- OSV: https://osv.dev/vulnerability/CVE-2026-98383

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98383/
Summaries are generated and may contain mistakes; the official description above is the record.