CVE-2026-63944

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync

hci_le_create_cis_sync() dereferences conn->conn_timeout after releasing

both rcu_read_lock() and hci_dev_lock(hdev). The conn pointer was

obtained from an RCU-protected iteration over hdev->conn_hash.list and

is not valid once these locks are dropped. A concurrent disconnect can

free the hci_conn between the unlock and the dereference, causing a

use-after-free read.

The cancellation mechanism in hci_conn_del() cannot prevent this because

hci_le_create_cis_pending() queues hci_create_cis_sync with data=NULL:

hci_cmd_sync_queue(hdev, hci_create_cis_sync, NULL, NULL);

While hci_conn_del() dequeues with data=conn:

hci_cmd_sync_dequeue(hdev, NULL, conn, NULL);

Since NULL != conn, the lookup in _hci_cmd_sync_lookup_entry() never

matches, and the pending work item is not cancelled.

Fix this by saving conn->conn_timeout into a local variable while the

lo

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References