5.5Medium

Linux Linux Kernel

CVE-2026-64405

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 this means for your business

  • It affects Linux Kernel. It matters if your company, or a supplier that handles your data, runs it.
  • An attacker can use it only with access to the machine itself, with an ordinary user login, and without anyone at your company clicking anything.
  • FIRST's prediction model gives it a 0.1% chance of attack attempts being seen in the next 30 days, ranking above 2% of all known flaws.

What to do

  1. 1Check whether your company or your suppliers run Linux Kernel, and which version. The affected versions are listed further down this page.
  2. 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

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Scoring

CVSS
5.5 (v3.1)
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-476
Assigned by
416baaa9-dc9f-4396-8d5f-8c081fb06d67

Dates

Published
2026-07-25
Last modified
2026-09-04
Sources
NVD

Affected products

  • Linux Linux Kernel6.1.83 - 6.1.118, 6.4.16 - 6.5, 6.5.3 - 6.6.145, 6.7 - 6.12.97, 6.13 - 6.18.39, 6.19 - 7.1.4, 7.2

As listed in the NVD configuration data. Not a statement about your estate.

References