# CVE-2026-68337: bpf: Reject redirect helpers without a bpf_net_context

> A local attacker with high privileges can cause a kernel crash by triggering a null pointer dereference in BPF redirect helpers when attached to specific qdiscs.

- **Severity:** Not scored
- **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:** 10 Aug 2026
- **Updated:** 21 Sep 2026
- **Also known as:** AZL-94701, BELL-CVE-2026-68337, DEBIAN-CVE-2026-68337, GHSA-r749-jhcj-5x93, UBUNTU-CVE-2026-68337

## What is CVE-2026-68337?

CVE-2026-68337 is a vulnerability in Linux, published on 10 Aug 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: Reject redirect helpers without a bpf_net_context

The bpf_redirect*() helpers and skb_do_redirect() obtain the per-task
bpf_redirect_info via bpf_net_ctx_get_ri(), which dereferences the
current->bpf_net_context unconditionally. That context is established
on the paths that run tc BPF such as sch_handle_{ingress,egress}(),
*except* for the case where {cls,act}_bpf was attached to a proper
qdisc. A program running from there reaches the NULL deref in two ways:

* It calls bpf_redirect() directly, which dereferences the context at
  the top of the helper:

     tc qdisc add dev eth0 root handle 1: red limit 1MB min 10KB max 20KB \
        avpkt 1000 burst 100 qevent early_drop block 10
     tc filter add block 10 pref 1 bpf obj redirect.o

* It simply returns TC_ACT_REDIRECT without helper call: tcf_qevent_handle()
  then dispatches to skb_do_redirect(), which dereferences the context

Rather than extending bpf_net_context management into the qdisc path,
make the redirect helpers refuse to operate when no context exists, and
have tcf_qevent_handle() drop a TC_ACT_REDIRECT verdict instead of
calling skb_do_redirect(). Previous behaviour was a crash, so nothing
regresses by not supporting it.

## Which versions are affected by CVE-2026-68337?


## How do I fix CVE-2026-68337?

Apply the vendor's patch.

## Is CVE-2026-68337 being exploited?

There is no known exploitation of CVE-2026-68337 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68337 and fix it if it is affected.

What it is: CVE-2026-68337 is a vulnerability in Linux, published on 10 Aug 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-2026-68337 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-2026-68337/ (Markdown: https://insights.sbomify.com/CVE-2026-68337/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68337
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68337
- OSV: https://osv.dev/vulnerability/CVE-2026-68337

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68337/
Summaries are generated and may contain mistakes; the official description above is the record.