CVE-2026-74509

Status: UPDATED  |  Advisory ID: CVE-2026-74509

Key Details

Affected Products, Subsystems & Sectors

What to Know

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

Bluetooth: hci_sync: Fix advertising data UAFs

hci_find_adv_instance() returns an adv_info pointer that is valid only

while hdev->lock is held. The advertising command-sync paths perform

instance lookups without that lock and, in some cases, retain the pointer

while waiting for a controller response.

An advertising termination event can therefore interleave as follows:

hci_cmd_sync_work hci_rx_work

hci_find_adv_instance()

__hci_cmd_sync_status()

wait for controller reply hci_dev_lock()

hci_remove_adv_instance()

kfree(adv)

adv->scan_rsp_changed = false

KASAN reported:

BUG: KASAN: slab-use-after-free in hci_set_ext_scan_rsp_data_sync+0x2e1/0x300

Write of size 1 at addr ffff88810a45d21d by task kworker/u17:0/88

Workqueue: hci0 hci_cmd_sync_work

Call Trace:

hci_set_ext_scan_rsp_data_sync+0x2e1/0x300

hci_schedule_adv_instance_sync+0x390/0x4c0

hci_cmd_sync_work+0x173/0x300

Allocated by task 87:

hci_add_adv_instance+0x538/0xac0

add_advertising+0x885/0x1160

Freed by task 89:

kfree+0x131/0x3c0

hci_remove_adv_instance+0x1d8/0x3b0

hci_le_ext_adv_term_evt+0x17b/0x730

Protect the instance lookup and payload construction in the extended

advertising, scan response, and periodic advertising data paths. Snapshot

the advertising parameters under hdev->lock, but release the lock before

waiting for the controller.

Clear advertising-data dirty bits before issuing their commands and

restore them after a failure using a fresh lookup. Likewise, update the

reported transmit power through a fresh lookup after the parameter command

completes. No adv_info pointer then survives an HCI command wait. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References