# CVE-2026-72066: cpu: hotplug: Bound hotplug states sysfs output

> A buffer overflow in the Linux kernel CPU hotplug sysfs output allows attackers to cause denial of service or 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:** 15 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-72066, DEBIAN-CVE-2026-72066, GHSA-58q4-579w-9x9r, UBUNTU-CVE-2026-72066

## What is CVE-2026-72066?

CVE-2026-72066 is a high-severity memory corruption 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:

cpu: hotplug: Bound hotplug states sysfs output

states_show() adds CPU hotplug state names into a single sysfs buffer
using sprintf(). With enough registered states, this can write past the
end of the PAGE_SIZE buffer.

Use sysfs_emit_at() so output is bounded.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2026-72066?


## How do I fix CVE-2026-72066?

Apply the vendor's patch.

## Is CVE-2026-72066 being exploited?

There is no known exploitation of CVE-2026-72066 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72066 and fix it if it is affected.

What it is: CVE-2026-72066 is a high-severity memory corruption 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-2026-72066 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-2026-72066/ (Markdown: https://insights.sbomify.com/CVE-2026-72066/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72066
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72066
- OSV: https://osv.dev/vulnerability/CVE-2026-72066

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72066/
Summaries are generated and may contain mistakes; the official description above is the record.