# CVE-2026-80575: Input: cs40l50-vibra - validate custom data from user space

> A local attacker can cause a kernel crash by providing invalid custom data lengths to the cs40l50-vibra input driver.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 26 Aug 2026
- **Updated:** 27 Aug 2026
- **Also known as:** BELL-CVE-2026-80575, DEBIAN-CVE-2026-80575, GHSA-6c2r-6hqv-3xph, UBUNTU-CVE-2026-80575

## What is CVE-2026-80575?

CVE-2026-80575 is a high-severity vulnerability in Linux, published on 26 Aug 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:

Input: cs40l50-vibra - validate custom data from user space

cs40l50_add() copies the custom data of an FF_PERIODIC/FF_CUSTOM effect
straight from the ff_effect the user passed to EVIOCSFF, without
requiring it to hold anything:

    work_data.custom_data = memdup_array_user(periodic->custom_data,
                                              periodic->custom_len,
                                              sizeof(s16));
    work_data.custom_len = periodic->custom_len;

The driver then reads two words out of that buffer: custom_data[0] as the
waveform bank in cs40l50_effect_bank_set(), and custom_data[1] as the
index within the bank in cs40l50_effect_index_set().  Neither read is
covered by a length check, and custom_len is fully user controlled:

  - custom_len == 0 makes memdup_array_user() call memdup_user() with a
    length of zero, which returns ZERO_SIZE_PTR rather than an error, so
    custom_data[0] dereferences it.

  - custom_len == 1 allocates two bytes.  A bank of ROM or RAM keeps
    effect->type out of the OWT case, and custom_data[1] is then read one
    word past the allocation.

The bank value itself is also mishandled.  It is masked with
CS40L50_CUSTOM_DATA_MASK (0xffff) but stored in an s16, so a
custom_data[0] of 0x8000 or above wraps to a negative value that passes
the "bank_type >= CS40L50_WVFRM_BANK_NUM" test.
cs40l50_effect_index_set() indexes vib->dsp.banks[] with it before the
switch statement's default case gets a chance to reject it:

    base_index = vib->dsp.banks[effect->type].base_index;
    max_index = vib->dsp.banks[effect->type].max_index;

Require the two words the driver reads to be present, and hold the masked
bank in a u32 so the existing upper-bound test covers the whole range.
The da7280 haptic driver already range checks custom_len this way.

## Which versions are affected by CVE-2026-80575?


## How do I fix CVE-2026-80575?

Apply the vendor's patch.

## Is CVE-2026-80575 being exploited?

There is no known exploitation of CVE-2026-80575 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80575 and fix it if it is affected.

What it is: CVE-2026-80575 is a high-severity vulnerability in Linux, published on 26 Aug 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-2026-80575 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-2026-80575/ (Markdown: https://insights.sbomify.com/CVE-2026-80575/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80575
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80575
- OSV: https://osv.dev/vulnerability/CVE-2026-80575

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80575/
Summaries are generated and may contain mistakes; the official description above is the record.