CVE-2025-40140: net: usb: Remove disruptive netif_wake_queue in rtl8150_set_multicast
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.
Security readout for executives and security teams
Plain-English summary
A Linux driver flaw can mishandle transmission synchronization for RTL8150 USB Ethernet adapters, allowing a transmit request to be submitted twice. This may cause kernel warnings or broader security impact. Systems not using the affected driver and hardware are less likely to be exposed.
Executive priority
Prioritize verification and patching on systems using RTL8150 USB Ethernet adapters, especially sensitive or high-availability hosts. Treat the rating seriously, but avoid assuming widespread exposure or active attacks without further evidence.
Technical view
The rtl8150 receive-mode callback could wake the transmit queue before an outstanding USB request completed. Another transmission could then resubmit the same URB. The kernel fix removes inappropriate transmit-queue operations because the networking core already synchronizes the callback.
Likely exposure
Exposure requires an affected Linux kernel and use of the rtl8150 USB networking driver, typically with compatible hardware attached. The supplied version data is ambiguous and includes commit identifiers, so distribution-specific exposure cannot be determined from it alone.
Exploitation context
The supplied CVSS score is 8.8 with adjacent attack vector and no required privileges or user interaction. However, the sources provide no demonstrated attack path, public exploit, or evidence of active exploitation. The CVE is not listed as KEV in the bundle.
Researcher notes
The reported condition is a queue-synchronization error producing duplicate URB submission. Syzbot found the warning, while the supplied material does not establish exploitability beyond the CVSS assessment. Exact affected and fixed distribution releases require vendor confirmation because the bundled version list is not sufficiently clear.
Mitigation direction
Apply a vendor-supported kernel update containing the relevant stable fix.
Check Linux distribution advisories for corrected package versions and backports.
Prioritize systems actively using RTL8150-compatible USB Ethernet hardware.
If patching is delayed, obtain temporary mitigation guidance from the kernel or distribution vendor.
Validation and detection
Inventory kernel versions and identify systems loading or using the rtl8150 driver.
Confirm installed kernel packages include a referenced stable fix or documented backport.
Review kernel logs for rtl8150_start_xmit or usb_submit_urb warnings.
Retest affected networking workloads after updating the kernel.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Potential ATT&CK relevance
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1CVSS vectors
3Timeline events
0ADP providers
9Source links
CVSS vector scores
1 official score
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