CVE-2025-40140

In the Linux kernel, the following vulnerability has been resolved:

net: usb: Remove disruptive netif_wake_queue in rtl8150_set_multicast

syzbot reported WARNING in rtl8150_start_xmit/usb_submit_urb. This is the sequence of events that leads to the warning:

rtl8150_start_xmit() { netif_stop_queue(); usb_submit_urb(dev->tx_urb); }

rtl8150_set_multicast() { netif_stop_queue(); netif_wake_queue(); <-- wakes up TX queue before URB is done }

rtl8150_start_xmit() { netif_stop_queue(); usb_submit_urb(dev->tx_urb); <-- double submission }

rtl8150_set_multicast being the ndo_set_rx_mode callback should not be calling netif_stop_queue and notif_start_queue as these handle TX queue synchronization.

The net core function dev_set_rx_mode handles the synchronization for rtl8150_set_multicast making it safe to remove these locks.

This vulnerability is rated as having Moderate impact for Red Hat Enterprise Linux because exploitation requires local access and depends on the presence of a specific Realtek RTL8150 USB network device. In typical server and enterprise deployments, legacy USB Ethernet hardware is rarely utilized, substantially limiting attack exposure. Successful exploitation requires triggering concurrent transmission and multicast mode changes, resulting in a kernel warning and denial of service rather than code execution or privilege escalation.

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.