# CVE-2026-93288: netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state

> A use-after-free vulnerability in the Linux kernel netfilter subsystem allows attackers to cause denial of service or potentially execute code.

- **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:** 24 Sep 2026
- **Updated:** 3 Oct 2026
- **Also known as:** AZL-103958, BELL-CVE-2026-93288, DEBIAN-CVE-2026-93288, GHSA-56j7-mrx8-v649, UBUNTU-CVE-2026-93288

## What is CVE-2026-93288?

CVE-2026-93288 is a high-severity use after free vulnerability in Linux, published on 24 Sep 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:

netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state

sashiko reports: "nfnl_log_net_exit() calls nf_log_unset(), which
clears the logger pointer without an RCU grace period.  Immediately after,
ops_free_list() frees the per-net state while concurrent packets might
still be executing nf_log_packet() under rcu_read_lock()."

Clear the pointer via .pre_exit to make sure rcu readers have completed
before pernet storage is free'd.  The change in nf_log_syslog.c is only
done for consistency: it doesn't use pernet data.

## Which versions are affected by CVE-2026-93288?


## How do I fix CVE-2026-93288?

Apply the vendor's patch.

## Is CVE-2026-93288 being exploited?

There is no known exploitation of CVE-2026-93288 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93288 and fix it if it is affected.

What it is: CVE-2026-93288 is a high-severity use after free vulnerability in Linux, published on 24 Sep 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-2026-93288 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-2026-93288/ (Markdown: https://insights.sbomify.com/CVE-2026-93288/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93288
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93288
- OSV: https://osv.dev/vulnerability/CVE-2026-93288

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93288/
Summaries are generated and may contain mistakes; the official description above is the record.