CVE-2026-99009 - In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: connect the session socket witho

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: connect the session socket without rfcomm_mutex An RFCOMM connect() issued while a BR/EDR link is being authenticated makes lockdep report a circular dependency, and the reported cycle is a real AB/BA between rfcomm_mutex and hdev->lock. rfcomm_security_cfm() is called from the HCI event path, which already holds hdev->lock: hci_rx_work() hci_event_packet() hci_cc_read_enc_key_size() [hdev->lock] hci_encrypt_cfm() [hci_cb_list_lock] rfcomm_security_cfm() [rfcomm_mutex] while an RFCOMM connect() from userspace takes the same two locks the other way round: rfcomm_sock_connect() rfcomm_dlc_open() [rfcomm_mutex] __rfcomm_dlc_open() rfcomm_session_create() kernel_connect() l2cap_sock_connect() l2cap_chan_connect() [hdev->lock] WARNING: possible circular locking dependency detected kworker/u131:1/1128 is trying to acquire lock: rfcomm_mutex, at: rfcomm_security_cfm+0x31/0x3e0 [rfcomm] but task is already holding lock: hci_cb_list_lock, at: hci_cc_read_enc_key_size+0x1d2/0xcc0 Chain exists of: rfcomm_mutex --> &hdev->lock --> hci_cb_list_lock hci_auth_complete_evt() and hci_encrypt_change_evt() reach the callback the same way. Both orders have to be seen in the same boot, which is why a BR/EDR connection alone is not enough to show it: a session set up by the remote side is created by rfcomm_accept_connection() in krfcommd, which calls kernel_accept() and never takes hdev->lock under rfcomm_mutex. Connecting a device that authenticates and encrypts the link and then calling connect() on an RFCOMM socket towards any address - the connect does not have to succeed, the order is recorded before the page timeout - reports it every time. Only the session socket has to be connected with the lock held, and it does not: nothing else can see the socket before i