# CVE-2026-93251: ACPI: bus: Introduce acpi_bus_get_primary_device()

> A use-after-free vulnerability in the Linux kernel ACPI bus allows local attackers to potentially execute code or escalate privileges via stale device pointers.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-103826, BELL-CVE-2026-93251, DEBIAN-CVE-2026-93251, GHSA-2qvg-p8g6-fm8w, UBUNTU-CVE-2026-93251

## What is CVE-2026-93251?

CVE-2026-93251 is an use after free vulnerability in Linux, published on 24 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:

ACPI: bus: Introduce acpi_bus_get_primary_device()

The function used for obtaining the first "physical" device for which
the given ACPI one is the ACPI companion, acpi_get_first_physical_node(),
may return a stale device pointer (mostly in theory) because
acpi_unbind_one() may run as a whole after dropping the ACPI device's
physical_node_lock in acpi_get_first_physical_node() and before it
returns.  The last reference to the "physical" device may be dropped
then before the pointer to it is returned to the caller.

If that happens and the acpi_get_first_physical_node() caller invokes
get_device() on the pointer obtained from it, which is done by the
majority of its callers, a use-after-free will occur.

To prepare for addressing this problem, introduce a new function for
getting the first "physical" device associated with the given ACPI one
(the "primary physical device") that will also reference count the
device in question before returning a pointer to it.

Make that new function and acpi_get_first_physical_node() share the
physical node list lookup code.

No intentional functional impact.

## Which versions are affected by CVE-2026-93251?


## How do I fix CVE-2026-93251?

Apply the vendor's patch.

## Is CVE-2026-93251 being exploited?

There is no known exploitation of CVE-2026-93251 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93251 and fix it if it is affected.

What it is: CVE-2026-93251 is an use after free vulnerability in Linux, published on 24 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-2026-93251 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-2026-93251/ (Markdown: https://insights.sbomify.com/CVE-2026-93251/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93251
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93251
- OSV: https://osv.dev/vulnerability/CVE-2026-93251

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93251/
Summaries are generated and may contain mistakes; the official description above is the record.