CVE-2026-23146: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.1% chance of exploitation in the next 30 days.

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.

Affected products

• Linux Linux Kernel: from 5.4.293, before 5.5 (fixed in 5.5); from 5.10.237, before 5.10.249 (fixed in 5.10.249); from 5.15.181, before 5.15.199 (fixed in 5.15.199); from 6.1.135, before 6.1.162 (fixed in 6.1.162); from 6.6.88, before 6.6.123 (fixed in 6.6.123); from 6.12.24, before 6.12.69 (fixed in 6.12.69); …

Published 2026-02-14. Last modified 2026-06-17.