# CVE-2026-90284: firmware_loader: do not queue completed sysfs fallback requests

> A race condition in the Linux kernel firmware loader can cause a use-after-free, leading to a system crash when a userspace helper completes a request prematurely.

- **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:** 19 Oct 2026
- **Also known as:** AZL-101912, BELL-CVE-2026-90284, DEBIAN-CVE-2026-90284, GHSA-97xh-425q-x269, UBUNTU-CVE-2026-90284

## What is CVE-2026-90284?

CVE-2026-90284 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:

firmware_loader: do not queue completed sysfs fallback requests

fw_load_sysfs_fallback() calls device_add() before adding the fw_priv to
pending_fw_head. device_add() publishes the fallback loading interface, so
a userspace helper which discovers the device by scanning sysfs can write 0
to the loading attribute and complete the request before it is queued as
pending.

In that interleaving firmware_loading_store() calls fw_state_done() while
pending_list still points to itself, so it cannot remove an entry from
pending_fw_head. The subsequent unconditional list_add() then queues an
already-completed fw_priv. Once the request is released, pending_fw_head
can retain a pointer to freed memory and the next fallback request can
fault while validating the list.

Only in-flight fallback requests need suspend or reboot abort handling. If
the request is already DONE after device_add(), return success from the
fallback path without sending another uevent, waiting again, or queueing it
as pending. This preserves the invariant that pending_fw_head contains only
active fallback requests.

## Which versions are affected by CVE-2026-90284?


## How do I fix CVE-2026-90284?

Apply the vendor's patch.

## Is CVE-2026-90284 being exploited?

There is no known exploitation of CVE-2026-90284 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90284 and fix it if it is affected.

What it is: CVE-2026-90284 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-2026-90284 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-2026-90284/ (Markdown: https://insights.sbomify.com/CVE-2026-90284/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90284
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90284
- OSV: https://osv.dev/vulnerability/CVE-2026-90284

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90284/
Summaries are generated and may contain mistakes; the official description above is the record.