# CVE-2025-68783: ALSA: usb-mixer: us16x08: validate meter packet indices

> A missing bounds check in the Linux kernel USB mixer driver allows out-of-bounds writes, potentially enabling local privilege escalation or code execution.

- **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:** 13 Jan 2026
- **Updated:** 11 May 2026
- **Also known as:** AZL-74372, BELL-CVE-2025-68783, DEBIAN-CVE-2025-68783, GHSA-8vvr-5pch-2fhg, ROOT-OS-DEBIAN-11-CVE-2025-68783, ROOT-OS-DEBIAN-12-CVE-2025-68783, ROOT-OS-DEBIAN-13-CVE-2025-68783, ROOT-OS-UBUNTU-2204-CVE-2025-68783, ROOT-OS-UBUNTU-2404-CVE-2025-68783, UBUNTU-CVE-2025-68783

## What is CVE-2025-68783?

CVE-2025-68783 is a memory corruption vulnerability in Linux, published on 13 Jan 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:

ALSA: usb-mixer: us16x08: validate meter packet indices

get_meter_levels_from_urb() parses the 64-byte meter packets sent by
the device and fills the per-channel arrays meter_level[],
comp_level[] and master_level[] in struct snd_us16x08_meter_store.

Currently the function derives the channel index directly from the
meter packet (MUB2(meter_urb, s) - 1) and uses it to index those
arrays without validating the range. If the packet contains a
negative or out-of-range channel number, the driver may write past
the end of these arrays.

Introduce a local channel variable and validate it before updating the
arrays. We reject negative indices, limit meter_level[] and
comp_level[] to SND_US16X08_MAX_CHANNELS, and guard master_level[]
updates with ARRAY_SIZE(master_level).

## Which versions are affected by CVE-2025-68783?


## How do I fix CVE-2025-68783?

Apply the vendor's patch.

## Is CVE-2025-68783 being exploited?

There is no known exploitation of CVE-2025-68783 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68783 and fix it if it is affected.

What it is: CVE-2025-68783 is a memory corruption vulnerability in Linux, published on 13 Jan 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-2025-68783 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-2025-68783/ (Markdown: https://insights.sbomify.com/CVE-2025-68783/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68783
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68783
- OSV: https://osv.dev/vulnerability/CVE-2025-68783

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68783/
Summaries are generated and may contain mistakes; the official description above is the record.