# CVE-2026-80780: HID: pidff: fix OOB write when hid->inputs is empty

> A malicious USB device can trigger an out-of-bounds write in the Linux kernel HID driver, potentially allowing code execution or privilege escalation.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 4 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-99650, BELL-CVE-2026-80780, DEBIAN-CVE-2026-80780, GHSA-rxff-7rcf-x4wj, UBUNTU-CVE-2026-80780

## What is CVE-2026-80780?

CVE-2026-80780 is a memory corruption vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

HID: pidff: fix OOB write when hid->inputs is empty

hid_pidff_init_with_quirks() derives its input_dev from

	list_entry(hid->inputs.next, struct hid_input, list)

without first checking that hid->inputs is non-empty.  The list member
of struct hid_input is at offset 0, so on an empty list list_entry()
yields &hid->inputs itself and the following hidinput->input load reads
an unrelated member of struct hid_device.  dev is then a type-confused
pointer, and force-feedback init writes through it: each
set_bit(FF_*, dev->ffbit) stores 8 bytes at dev + 192, past the end of
the object dev actually aliases, and input_ff_create() adds further
writes of a heap pointer and two function pointers.

Until hid-universal-pidff the only caller was hid_pidff_init() from
usbhid, which runs under HID_CLAIMED_INPUT and therefore always has at
least one hid_input.  universal_pidff_probe() starts the device with
HID_CONNECT_DEFAULT & ~HID_CONNECT_FF and then calls
hid_pidff_init_with_quirks() directly whenever the descriptor carries a
PID usage page, bypassing that gate.  A report descriptor whose only
application collection is on HID_UP_PID leaves hid->inputs empty while
hid_connect() still succeeds through the hidraw claim, so probe reaches
the unguarded list_entry().

The write happens in the USB probe path, on the hotplug workqueue, so
plugging in a malicious device is enough to trigger it; no attacker
software and no logged-in user are required.  KASAN reports an 8-byte
out-of-bounds write in hid_pidff_init_with_quirks() reached from
universal_pidff_probe().

Check for an empty list before deriving dev and return -ENODEV, as the
other HID force-feedback drivers already do.  universal_pidff_probe()
propagates the error and unwinds.

Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>

## Which versions are affected by CVE-2026-80780?


## How do I fix CVE-2026-80780?

Apply the vendor's patch.

## Is CVE-2026-80780 being exploited?

There is no known exploitation of CVE-2026-80780 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80780 and fix it if it is affected.

What it is: CVE-2026-80780 is a memory corruption vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-80780 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-2026-80780/ (Markdown: https://insights.sbomify.com/CVE-2026-80780/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80780
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80780
- OSV: https://osv.dev/vulnerability/CVE-2026-80780

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80780/
Summaries are generated and may contain mistakes; the official description above is the record.