CVE-2025-21689 Information

Feb 11, 2025 cve

Description

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\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.

Reference

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