# CVE-2026-72127: netdev-genl: report NAPI thread PID in the caller's pid namespace

> A local attacker in a child PID namespace can leak global kernel thread PIDs via netdev-genl, bypassing namespace isolation.

- **Severity:** Not scored
- **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:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-72127, DEBIAN-CVE-2026-72127, GHSA-hx9w-mw8p-76q2, UBUNTU-CVE-2026-72127

## What is CVE-2026-72127?

CVE-2026-72127 is a vulnerability in Linux, published on 15 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:

netdev-genl: report NAPI thread PID in the caller's pid namespace

netdev_nl_napi_fill_one() reports the NAPI kthread PID in NETDEV_A_NAPI_PID
using task_pid_nr(), which returns the PID in the initial pid namespace.

NETDEV_CMD_NAPI_GET does not have GENL_ADMIN_PERM and the netdev genl family
is netnsok, so a caller in a child pid namespace can issue it. That caller
then sees the kthread's global PID, even though the kthread is not visible
in its pid namespace, where the value should be 0.

Translate the PID through the caller's pid namespace, the same way commit
3799c2570982 ("io_uring/fdinfo: translate SqThread PID through caller's
pid_ns") did for the io_uring SQPOLL thread. The doit and dumpit paths both
run synchronously in the caller's context, so task_active_pid_ns(current) is
the caller's pid namespace.

## Which versions are affected by CVE-2026-72127?


## How do I fix CVE-2026-72127?

Apply the vendor's patch.

## Is CVE-2026-72127 being exploited?

There is no known exploitation of CVE-2026-72127 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72127 and fix it if it is affected.

What it is: CVE-2026-72127 is a vulnerability in Linux, published on 15 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-2026-72127 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-2026-72127/ (Markdown: https://insights.sbomify.com/CVE-2026-72127/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72127
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72127
- OSV: https://osv.dev/vulnerability/CVE-2026-72127

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72127/
Summaries are generated and may contain mistakes; the official description above is the record.