CVE-2026-23146 Bluetooth: hci_uart: fix null-ptr-deref in hci_uart_write_work
A race condition in the Linux kernel Bluetooth driver causes a null pointer dereference, leading to a system crash.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-23146?
CVE-2026-23146 is a medium-severity vulnerability in Linux kernel, published on 14 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_uart: fix null-ptr-deref in hci_uart_write_work
hci_uart_set_proto() sets HCI_UART_PROTO_INIT before calling hci_uart_register_dev(), which calls proto->open() to initialize hu->priv. However, if a TTY write wakeup occurs during this window, hci_uart_tx_wakeup() may schedule write_work before hu->priv is initialized, leading to a NULL pointer dereference in hci_uart_write_work() when proto->dequeue() accesses hu->priv.
The race condition is:
CPU0 CPU1 ---- ---- hci_uart_set_proto() set_bit(HCI_UART_PROTO_INIT) hci_uart_register_dev() tty write wakeup hci_uart_tty_wakeup() hci_uart_tx_wakeup() schedule_work(&hu->write_work) proto->open(hu) // initializes hu->priv hci_uart_write_work() hci_uart_dequeue() proto->dequeue(hu) // accesses hu->priv (NULL!)
Fix this by moving set_bit(HCI_UART_PROTO_INIT) after proto->open() succeeds, ensuring hu->priv is initialized before any work can be scheduled.
Which versions are affected by CVE-2026-23146?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-23146?
Apply the vendor's patch.
Is CVE-2026-23146 being exploited?
There is no known exploitation of CVE-2026-23146 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-23146, DEBIAN-CVE-2026-23146, GHSA-hcr8-x92w-q652, ROOT-OS-UBUNTU-2204-CVE-2026-23146, ROOT-OS-UBUNTU-2404-CVE-2026-23146, UBUNTU-CVE-2026-23146.