# CVE-2026-93150: cgroup/cpuset: Make nr_deadline_tasks an atomic_t

> A race condition in the Linux kernel cpuset subsystem can corrupt task counters, potentially leading to system instability or privilege escalation.

- **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:** 21 Oct 2026
- **Also known as:** AZL-101855, BELL-CVE-2026-93150, DEBIAN-CVE-2026-93150, GHSA-rm22-rvmg-2466, UBUNTU-CVE-2026-93150

## What is CVE-2026-93150?

CVE-2026-93150 is a 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:

cgroup/cpuset: Make nr_deadline_tasks an atomic_t

The nr_deadline_tasks variable in the cpuset structure was introduced by
commit 6c24849f5515 ("sched/cpuset: Keep track of SCHED_DEADLINE task
in cpusets"). It is reported by sashiko [1] that nr_deadline_tasks
can currently be modified by inc_dl_tasks_cs() under rq->lock and
by cpuset_attach() under cpuset_mutex. So if both updates happen
simultaneously, the nr_deadline_tasks variable can be corrupted leading
to incorrect operations down the road.

Fix that by changing its type to atomic_t so that nr_deadline_tasks
are always atomically updated. This fix patch is a low hanging fruit.
It can handle some of the races between a concurrent sched_setscheduler()
and cpuset_can_attach()/cpuset_attach() calls, but not all of them like
the other issue raised by sashiko [2]. This will be handled hopefully
in a future follow up patch.

[1] https://sashiko.dev/#/patchset/20260626181923.133658-1-longman%40redhat.com
[2] https://sashiko.dev/#/patchset/20260630033344.352702-1-longman%40redhat.com

## Which versions are affected by CVE-2026-93150?


## How do I fix CVE-2026-93150?

Apply the vendor's patch.

## Is CVE-2026-93150 being exploited?

There is no known exploitation of CVE-2026-93150 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93150 and fix it if it is affected.

What it is: CVE-2026-93150 is a 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-2026-93150 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-2026-93150/ (Markdown: https://insights.sbomify.com/CVE-2026-93150/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93150
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93150
- OSV: https://osv.dev/vulnerability/CVE-2026-93150

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93150/
Summaries are generated and may contain mistakes; the official description above is the record.