Bug 2467218 (CVE-2026-43180)

Summary: CVE-2026-43180 kernel: net: usb: kaweth: remove TX queue manipulation in kaweth_set_rx_mode
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's kaweth USB network driver. The kaweth_set_rx_mode() function incorrectly manipulates the transmit (TX) queue, allowing it to be re-enabled while a USB Request Block (URB) is still active. This can result in the same URB being submitted twice, leading to a kernel warning and potentially causing system instability or a denial of service (DoS).
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Description OSIDB Bzimport 2026-05-06 13:11:28 UTC
In the Linux kernel, the following vulnerability has been resolved:

net: usb: kaweth: remove TX queue manipulation in kaweth_set_rx_mode

kaweth_set_rx_mode(), the ndo_set_rx_mode callback, calls
netif_stop_queue() and netif_wake_queue(). These are TX queue flow
control functions unrelated to RX multicast configuration.

The premature netif_wake_queue() can re-enable TX while tx_urb is still
in-flight, leading to a double usb_submit_urb() on the same URB:

kaweth_start_xmit() {
    netif_stop_queue();
    usb_submit_urb(kaweth->tx_urb);
}

kaweth_set_rx_mode() {
    netif_stop_queue();
    netif_wake_queue();             // wakes TX queue before URB is done
}

kaweth_start_xmit() {
    netif_stop_queue();
    usb_submit_urb(kaweth->tx_urb); // URB submitted while active
}

This triggers the WARN in usb_submit_urb():

  "URB submitted while active"

This is a similar class of bug fixed in rtl8150 by

- commit 958baf5eaee3 ("net: usb: Remove disruptive netif_wake_queue in rtl8150_set_multicast").

Also kaweth_set_rx_mode() is already functionally broken, the
real set_rx_mode action is performed by kaweth_async_set_rx_mode(),
which in turn is not a no-op only at ndo_open() time.