# CVE-2026-97608: netfilter: nf_log: unregister loggers before per-net teardown

> A race condition in Linux kernel netfilter logging allows attackers to trigger use-after-free errors, potentially leading to code execution or system crashes.

- **Severity:** High 7.0 (`CVSS:3.1/AV:L/AC:H/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:** 25 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-104738, BELL-CVE-2026-97608, DEBIAN-CVE-2026-97608, GHSA-gqgj-ww6j-qxj3, UBUNTU-CVE-2026-97608

## What is CVE-2026-97608?

CVE-2026-97608 is a high-severity vulnerability in Linux, published on 25 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: nf_log: unregister loggers before per-net teardown

nf_log_syslog and nfnetlink_log unregister their per-network namespace
operations before unregistering their global logger backends. This
leaves a window where a sysctl or netlink writer can rebind the still-
registered logger after the per-net pre-exit callback cleared the old
selection.

The race looks like this:

  CPU 0                                 CPU 1
  ----                                  ----
  unregister_pernet_subsys()
    nf_log_unset(net, logger)
      net->nf.nf_loggers[pf] = NULL

                                        lock nf_log_mutex
                                        find logger in loggers[][]
                                        net->nf.nf_loggers[pf] = logger
                                        unlock nf_log_mutex

  nf_log_unregister(logger)
    lock nf_log_mutex
    loggers[pf][type] = NULL
    unlock nf_log_mutex
    synchronize_rcu()
  module exit returns
  module core frees backend memory

Later, a sysctl read or packet logging operation can dereference the
stale per-net logger pointer.

Fix this by unregistering the global logger backends before tearing down
per-net state. Once the global registrations are gone, later writers can
no longer rebind the logger. unregister_pernet_subsys() already waits
for an RCU grace period after the pre-exit callback clears the per-net
selection, while nf_log_unregister() continues to cover readers of the
global logger table.

Apply this ordering fix to both nf_log backends that combine per-net
teardown with global logger registration.

## Which versions are affected by CVE-2026-97608?


## How do I fix CVE-2026-97608?

Apply the vendor's patch.

## Is CVE-2026-97608 being exploited?

There is no known exploitation of CVE-2026-97608 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97608 and fix it if it is affected.

What it is: CVE-2026-97608 is a high-severity vulnerability in Linux, published on 25 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-2026-97608 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-2026-97608/ (Markdown: https://insights.sbomify.com/CVE-2026-97608/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97608
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97608
- OSV: https://osv.dev/vulnerability/CVE-2026-97608

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97608/
Summaries are generated and may contain mistakes; the official description above is the record.