CVE-2025-21689

In the Linux kernel, the following vulnerability has been resolved: USB: serial: quatech2: fix null-ptr-deref in qt2_process_read_urb() This patch addresses a null-ptr-deref in qt2_process_read_urb() due to an incorrect bounds check in the following: if (newport > serial->num_ports) { dev_err(&port->dev, "%s - port change to invalid port: %i\n", __func__, newport); break; } The condition doesn't account for the valid range of the serial->port buffer, which is from 0 to serial->num_ports - 1. When newport is equal to serial->num_ports, the assignment of "port" in the following code is out-of-bounds and NULL: serial_priv->current_port = newport; port = serial->port[serial_priv->current_port]; The fix checks if newport is greater than or equal to serial->num_ports indicating it is out-of-bounds.

• linux linux kernel (>= 3.5 < 5.4.290) • linux linux kernel (>= 5.5 < 5.10.234) • linux linux kernel (>= 5.11 < 5.15.178) • linux linux kernel (>= 5.16 < 6.1.128) • linux linux kernel (>= 6.2 < 6.6.75) • linux linux kernel (>= 6.7 < 6.12.12) • linux linux kernel 6.13