# CVE-2026-90077: net: fix a resource leak in copy_net_ns() error handling path

> A resource leak in the Linux kernel network namespace creation allows local attackers to exhaust system resources, causing denial of service.

- **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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-90077, DEBIAN-CVE-2026-90077, GHSA-gwpv-9h8f-9f72, UBUNTU-CVE-2026-90077

## What is CVE-2026-90077?

CVE-2026-90077 is a denial of service vulnerability in Linux, published on 17 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:

net: fix a resource leak in copy_net_ns() error handling path

Currently, preinit_net() does two things:

  (1) call ns_common_init() which might fail
  (2) initialize resources which does not fail

However, preinit_net() is returning early when (1) fails, and copy_net_ns()
is jumping to the dec_ucounts: label. As a result, resources allocated by
net_alloc() are leaking. We need to call key_remove_domain() and
net_passive_dec() in order to release resources allocated by net_alloc().

We cannot simply jump to the put_userns: label when preinit_net() failed,
for (2) is not yet done. But we can reorder (1) and (2), for there is no
dependency between (1) and (2). Therefore, this patch decouples (1) from
preinit_net() and changes preinit_net() back to a void function, and calls
ns_common_init() after preinit_net() succeeded. Then, we can jump to
immediately after ns_common_free() of the put_userns: label.

## Which versions are affected by CVE-2026-90077?


## How do I fix CVE-2026-90077?

Apply the vendor's patch.

## Is CVE-2026-90077 being exploited?

There is no known exploitation of CVE-2026-90077 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90077 and fix it if it is affected.

What it is: CVE-2026-90077 is a denial of service vulnerability in Linux, published on 17 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-2026-90077 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-2026-90077/ (Markdown: https://insights.sbomify.com/CVE-2026-90077/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90077
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90077
- OSV: https://osv.dev/vulnerability/CVE-2026-90077

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90077/
Summaries are generated and may contain mistakes; the official description above is the record.