# CVE-2026-74679: usb: gadget: f_ncm: Use unsigned int for ndp_index

> A malicious USB host can trigger an integer overflow in the Linux kernel NCM gadget driver, leading to an out-of-bounds memory read.

- **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:** 22 Aug 2026
- **Updated:** 22 Aug 2026
- **Also known as:** BELL-CVE-2026-74679, DEBIAN-CVE-2026-74679, GHSA-6qhg-x625-34c5, UBUNTU-CVE-2026-74679

## What is CVE-2026-74679?

CVE-2026-74679 is a vulnerability in Linux, published on 22 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:

usb: gadget: f_ncm: Use unsigned int for ndp_index

The variable ndp_index is declared as a signed integer, but it stores
the return value of get_ncm(), which is unsigned.

A malicious host can supply a large offset that overflows the signed
ndp_index, making it negative. Because ndp_index is compared against
unsigned bounds, this negative value bypasses sanity checks and leads
to an out-of-bounds read when calculating the address of the NDP
block (ntb_ptr + ndp_index).

Fix this by changing ndp_index to unsigned int to ensure consistent
unsigned comparisons throughout the function.

## Which versions are affected by CVE-2026-74679?


## How do I fix CVE-2026-74679?

Apply the vendor's patch.

## Is CVE-2026-74679 being exploited?

There is no known exploitation of CVE-2026-74679 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74679 and fix it if it is affected.

What it is: CVE-2026-74679 is a vulnerability in Linux, published on 22 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-2026-74679 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-2026-74679/ (Markdown: https://insights.sbomify.com/CVE-2026-74679/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74679
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74679
- OSV: https://osv.dev/vulnerability/CVE-2026-74679

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74679/
Summaries are generated and may contain mistakes; the official description above is the record.