CVE-2026-46111
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
A vulnerability related to Bluetooth in the Linux kernel has been fixed, which could lead to a use-after-free error in the create_big_sync function. An additional check, hci_conn_valid(), was introduced to detect stale connections before BIG creation.
Risk Assessment
The lack of proper safeguards could lead to unauthorized access or system crashes, jeopardizing the integrity and availability of Bluetooth services within the organization.
Recommendation
It is recommended to update the Linux kernel to the latest version to mitigate this vulnerability and to implement monitoring of Bluetooth connections to detect potential issues.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_conn: fix potential UAF in create_big_sync Add hci_conn_valid() check in create_big_sync() to detect stale connections before proceeding with BIG creation. Handle the resulting -ECANCELED in create_big_complete() and re-validate the connection under hci_dev_lock() before dereferencing, matching the pattern used by create_le_conn_complete() and create_pa_complete(). Keep the hci_conn object alive across the async boundary by taking a reference via hci_conn_get() when queueing create_big_sync(), and dropping it in the completion callback. The refcount and the lock are complementary: the refcount keeps the object allocated, while hci_dev_lock() serializes hci_conn_hash_del()'s list_del_rcu() on hdev->conn_hash, as required by hci_conn_del(). hci_conn_put() is called outside hci_dev_unlock() so the final put (which resolves to kfree() via bt_link_release) does not run under hdev->lock, though the release path would be safe either way. Without this, create_big_complete() would unconditionally dereference the conn pointer on error, causing a use-after-free via hci_connect_cfm() and hci_conn_del().