# CVE-2026-92521: ACPI: PCI: Clear driver_data on all paths that free the acpi_pci_root

> A use-after-free vulnerability in the Linux kernel ACPI PCI subsystem allows local attackers to cause denial of service or potentially execute code via dangling 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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-102986, BELL-CVE-2026-92521, DEBIAN-CVE-2026-92521, GHSA-5pq6-vgcp-vv3f, UBUNTU-CVE-2026-92521

## What is CVE-2026-92521?

CVE-2026-92521 is an use after free 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:

ACPI: PCI: Clear driver_data on all paths that free the acpi_pci_root

acpi_pci_root_add() assigns the freshly allocated root to
device->driver_data before dmar_device_add() and pci_acpi_scan_root().
Both failure paths reach the end: label where root is kfree()'d, but
only the pci_acpi_scan_root() path clears driver_data first.

When dmar_device_add() fails during a hot-add, root is freed while
device->driver_data still points at it.  The ACPI core does not clear
driver_data on attach failure, so a later acpi_pci_find_root() call may
dereference this dangling pointer.

acpi_pci_root_remove() has the same problem: it frees root without
clearing device->driver_data, leaving a dangling pointer behind after
the root bridge is removed.

Move the NULL assignment to the shared end: label so every error path in
acpi_pci_root_add() clears driver_data before freeing root, and clear it
in acpi_pci_root_remove() as well, so the object is never left reachable
through driver_data after being freed.

## Which versions are affected by CVE-2026-92521?


## How do I fix CVE-2026-92521?

Apply the vendor's patch.

## Is CVE-2026-92521 being exploited?

There is no known exploitation of CVE-2026-92521 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-92521 and fix it if it is affected.

What it is: CVE-2026-92521 is an use after free 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-2026-92521 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-2026-92521/ (Markdown: https://insights.sbomify.com/CVE-2026-92521/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-92521
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-92521
- OSV: https://osv.dev/vulnerability/CVE-2026-92521

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-92521/
Summaries are generated and may contain mistakes; the official description above is the record.