# CVE-2026-23448: net: usb: cdc_ncm: add ndpoffset to NDP16 nframes bounds check

> A missing bounds check in the Linux kernel's CDC NCM USB driver allows out-of-bounds memory reads, potentially leading to crashes or code execution.

- **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:** 3 Apr 2026
- **Updated:** 14 Sep 2026
- **Also known as:** BELL-CVE-2026-23448, DEBIAN-CVE-2026-23448, GHSA-pjhh-88pp-3hg6, ROOT-OS-DEBIAN-11-CVE-2026-23448, ROOT-OS-DEBIAN-12-CVE-2026-23448, ROOT-OS-DEBIAN-13-CVE-2026-23448, ROOT-OS-UBUNTU-2204-CVE-2026-23448, ROOT-OS-UBUNTU-2404-CVE-2026-23448, UBUNTU-CVE-2026-23448

## What is CVE-2026-23448?

CVE-2026-23448 is a high-severity memory corruption vulnerability in Linux kernel, published on 3 Apr 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:

net: usb: cdc_ncm: add ndpoffset to NDP16 nframes bounds check

cdc_ncm_rx_verify_ndp16() validates that the NDP header and its DPE
entries fit within the skb. The first check correctly accounts for
ndpoffset:

  if ((ndpoffset + sizeof(struct usb_cdc_ncm_ndp16)) > skb_in->len)

but the second check omits it:

  if ((sizeof(struct usb_cdc_ncm_ndp16) +
       ret * (sizeof(struct usb_cdc_ncm_dpe16))) > skb_in->len)

This validates the DPE array size against the total skb length as if
the NDP were at offset 0, rather than at ndpoffset. When the NDP is
placed near the end of the NTB (large wNdpIndex), the DPE entries can
extend past the skb data buffer even though the check passes.
cdc_ncm_rx_fixup() then reads out-of-bounds memory when iterating
the DPE array.

Add ndpoffset to the nframes bounds check and use struct_size_t() to
express the NDP-plus-DPE-array size more clearly.

Weakness: CWE-129 (Improper Validation of Array Index)

## Which versions are affected by CVE-2026-23448?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23448?

Apply the vendor's patch.

## Is CVE-2026-23448 being exploited?

There is no known exploitation of CVE-2026-23448 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23448 and fix it if it is affected.

What it is: CVE-2026-23448 is a high-severity memory corruption vulnerability in Linux kernel, published on 3 Apr 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-2026-23448 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-23448/ (Markdown: https://insights.sbomify.com/CVE-2026-23448/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23448
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23448
- OSV: https://osv.dev/vulnerability/CVE-2026-23448

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23448/
Summaries are generated and may contain mistakes; the official description above is the record.