# CVE-2026-90089: Bluetooth: btnxpuart: Validate the FW dump header length

> A missing length check in the Linux kernel Bluetooth driver allows a truncated frame to cause an out-of-bounds read and premature controller reset, leading to denial of service.

- **Severity:** High 7.1 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H`)
- **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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-90089, DEBIAN-CVE-2026-90089, GHSA-h4rm-3g3v-jqmp, UBUNTU-CVE-2026-90089

## What is CVE-2026-90089?

CVE-2026-90089 is a high-severity vulnerability in Linux, published on 17 Sep 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:

Bluetooth: btnxpuart: Validate the FW dump header length

nxp_process_fw_dump() pulls the ACL header off the frame and then reads
seq_num and buf_len from a struct nxp_fw_dump_hdr placed at skb->data,
without checking that the ACL payload is long enough to contain it.

h4_recv_buf() collects HCI_ACL_HDR_SIZE bytes of header followed by the
number of payload bytes named in that header, so skb->len is 4 + dlen
with dlen supplied by the controller and possibly smaller than the 8
byte dump header, or zero. A short frame with connection handle 0xfff
therefore reads both fields from beyond the received data.

Beyond the read itself, buf_len is what terminates a dump: a value of
zero makes the driver call hci_devcd_complete() and reset the
controller, so a truncated frame can end a dump early.

Use skb_pull_data() to validate and pull the FW dump header before
accessing its fields. Warn and reject the chunk if the header is
truncated.

## Which versions are affected by CVE-2026-90089?


## How do I fix CVE-2026-90089?

Apply the vendor's patch.

## Is CVE-2026-90089 being exploited?

There is no known exploitation of CVE-2026-90089 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90089 and fix it if it is affected.

What it is: CVE-2026-90089 is a high-severity vulnerability in Linux, published on 17 Sep 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-2026-90089 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-2026-90089/ (Markdown: https://insights.sbomify.com/CVE-2026-90089/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90089
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90089
- OSV: https://osv.dev/vulnerability/CVE-2026-90089

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90089/
Summaries are generated and may contain mistakes; the official description above is the record.