# CVE-2026-72136: xfrm: xfrm_interface: require CAP_NET_ADMIN in the device netns for changelink

> A local attacker with CAP_NET_ADMIN in one network namespace can modify interfaces in another, leading to privilege escalation.

- **Severity:** High 8.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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:** 15 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-72136, DEBIAN-CVE-2026-72136, GHSA-87pp-x9f9-85hx, UBUNTU-CVE-2026-72136

## What is CVE-2026-72136?

CVE-2026-72136 is a high-severity 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:

xfrm: xfrm_interface: require CAP_NET_ADMIN in the device netns for changelink

xfrmi_changelink() operates on at most two netns, dev_net(dev) and the
interface link netns xi->net. They differ once the device is created in
or moved to a netns other than the one the request runs in. The rtnl
changelink path checks CAP_NET_ADMIN only against dev_net(dev), so a
caller privileged there but not in xi->net can rewrite an interface that
lives in xi->net.

Gate xfrmi_changelink() on rtnl_dev_link_net_capable() at its top,
before any attribute is parsed.

## Which versions are affected by CVE-2026-72136?


## How do I fix CVE-2026-72136?

Apply the vendor's patch.

## Is CVE-2026-72136 being exploited?

There is no known exploitation of CVE-2026-72136 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72136 and fix it if it is affected.

What it is: CVE-2026-72136 is a high-severity 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-2026-72136 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-2026-72136/ (Markdown: https://insights.sbomify.com/CVE-2026-72136/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72136
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72136
- OSV: https://osv.dev/vulnerability/CVE-2026-72136

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72136/
Summaries are generated and may contain mistakes; the official description above is the record.