# CVE-2026-64573: Bluetooth: qca: fix NVM tag length underflow in TLV parser

> An integer underflow in the Linux kernel Bluetooth driver allows out-of-bounds reads and writes, potentially causing crashes 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:** 5 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** AZL-94470, BELL-CVE-2026-64573, DEBIAN-CVE-2026-64573, GHSA-xx6f-xq9m-7gmm, UBUNTU-CVE-2026-64573

## What is CVE-2026-64573?

CVE-2026-64573 is a vulnerability in Linux, published on 5 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:

Bluetooth: qca: fix NVM tag length underflow in TLV parser

In the TLV_TYPE_NVM branch of qca_tlv_check_data() the tag loop bound is
"while (idx < length - sizeof(struct tlv_type_nvm))". "length" is a signed
int from the firmware TLV header and sizeof(struct tlv_type_nvm) is a
size_t (12), so "length" is converted to size_t and any firmware-supplied
"length" < 12 makes the subtraction wrap to a huge value. The loop body
then reads a 12-byte struct tlv_type_nvm past the end of the short
vmalloc'd firmware buffer (and the EDL_TAG_ID_* handlers can write past it).

Rewrite the bound as "idx + sizeof(struct tlv_type_nvm) <= length"; both
operands are non-negative, so it no longer underflows and a "length" too
small for one record correctly skips the loop.

  BUG: KASAN: vmalloc-out-of-bounds in qca_download_firmware.isra.0 (drivers/bluetooth/btqca.c:421)
  Read of size 2 at addr ffffc900000e5004 by task kworker/u9:0/52
  Workqueue: hci0 hci_power_on
  Call Trace:
   ...
   kasan_report (mm/kasan/report.c:595)
   qca_download_firmware.isra.0 (drivers/bluetooth/btqca.c:421 drivers/bluetooth/btqca.c:617)
   qca_uart_setup (drivers/bluetooth/btqca.c:948)
   qca_setup (drivers/bluetooth/hci_qca.c:2029)
   hci_uart_setup (drivers/bluetooth/hci_ldisc.c:438)
   hci_dev_open_sync (net/bluetooth/hci_sync.c:5227)
   hci_power_on (net/bluetooth/hci_core.c:920)
   process_one_work (kernel/workqueue.c:3322)
   worker_thread (kernel/workqueue.c:3486)
   kthread (kernel/kthread.c:436)
   ret_from_fork (arch/x86/kernel/process.c:158)
   ret_from_fork_asm (arch/x86/entry/entry_64.S:245)

## Which versions are affected by CVE-2026-64573?


## How do I fix CVE-2026-64573?

Apply the vendor's patch.

## Is CVE-2026-64573 being exploited?

There is no known exploitation of CVE-2026-64573 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64573 and fix it if it is affected.

What it is: CVE-2026-64573 is a vulnerability in Linux, published on 5 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-2026-64573 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-2026-64573/ (Markdown: https://insights.sbomify.com/CVE-2026-64573/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64573
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64573
- OSV: https://osv.dev/vulnerability/CVE-2026-64573

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64573/
Summaries are generated and may contain mistakes; the official description above is the record.