# CVE-2026-68399: bpf: Fix UAF in sock clone early bailouts

> A use-after-free in the Linux kernel BPF subsystem allows attackers to execute arbitrary code or escalate privileges via socket cloning.

- **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:** 10 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-94890, BELL-CVE-2026-68399, DEBIAN-CVE-2026-68399, GHSA-f9jq-9v6w-22v9, UBUNTU-CVE-2026-68399

## What is CVE-2026-68399?

CVE-2026-68399 is a high-severity use after free 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: Fix UAF in sock clone early bailouts

Similar to recent commit 9b51a6155d14 ("bpf,fork: wipe ->bpf_storage
before bailouts that access it"), sk_clone() performs an initial
shallow copy of the socket field ->sk_bpf_storage via sock_copy()
for the cloned socket newsk.

If sk_clone() bails out early (e.g. if sk_filter_charge() fails) prior
to calling bpf_sk_storage_clone(), newsk->sk_bpf_storage still points
to the parent socket's BPF local storage. When newsk is subsequently
freed via sk_free(), the deallocation path (__sk_destruct() ->
bpf_sk_storage_free()) destroys the parent socket's BPF local storage,
leading to a use-after-free (UAF) on the parent socket.

Fix this by resetting newsk->sk_bpf_storage to NULL immediately after
sock_copy() in sk_clone(), and remove the now redundant initialization
from bpf_sk_storage_clone().

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-68399?


## How do I fix CVE-2026-68399?

Apply the vendor's patch.

## Is CVE-2026-68399 being exploited?

There is no known exploitation of CVE-2026-68399 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68399 and fix it if it is affected.

What it is: CVE-2026-68399 is a high-severity use after free 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-2026-68399 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-2026-68399/ (Markdown: https://insights.sbomify.com/CVE-2026-68399/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68399
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68399
- OSV: https://osv.dev/vulnerability/CVE-2026-68399

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68399/
Summaries are generated and may contain mistakes; the official description above is the record.