CVE-2026-23146

A flaw was found in the Linux kernel's Bluetooth HCI UART driver. A race condition exists where the hci_uart_write_work() function may attempt to access uninitialized private data if a TTY write wakeup occurs during the protocol initialization phase. This can lead to a NULL pointer dereference, potentially causing a system crash and resulting in a Denial of Service (DoS).

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent the hci_uart kernel module from loading. This can be achieved by creating a blacklist file for the module.

Create a file named /etc/modprobe.d/blacklist-hci_uart.conf with the following content:

blacklist hci_uart
install hci_uart /bin/true

After creating the file, regenerate the initramfs to ensure the blacklist is applied during boot:

For RHEL 9 and 10: sudo dracut -f -v

For RHEL 6 ELS: sudo dracut -f

A reboot is required for the changes to take effect. This mitigation will disable Bluetooth HCI UART functionality, which may impact systems relying on this driver for Bluetooth communication.