CVE-2026-31722: usb: gadget: f_rndis: Fix net_device lifecycle with device_move
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: frndis: Fix netdevice lifecycle with devicemove
The netdevice is allocated during function instance creation and registered during the bind phase with the gadget device as its sysfs parent. When the function unbinds, the parent device is destroyed, but the netdevice survives, resulting in dangling sysfs symlinks:
console:/ # ls -l /sys/class/net/usb0 lrwxrwxrwx ... /sys/class/net/usb0 -> /sys/devices/platform/.../gadget.0/net/usb0 console:/ # ls -l /sys/devices/platform/.../gadget.0/net/usb0 ls: .../gadget.0/net/usb0: No such file or directory
Use devicemove() to reparent the netdevice between the gadget device tree and /sys/devices/virtual across bind and unbind cycles. During the final unbind, calling devicemove(NULL) moves the netdevice to the virtual device tree before the gadget device is destroyed. On rebinding, devicemove() reparents the device back under the new gadget, ensuring proper sysfs topology and power management ordering.
To maintain compatibility with legacy composite drivers (e.g., multi.c), the borrowednet flag is used to indicate whether the network device is shared and pre-registered during the legacy driver's bind phase.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.12.85-1 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.1.191 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.6.160 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.12.81 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.18.22 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.19.12 - Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.12.107-1Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1 - Upgrade
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ubuntu/linux-aws-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1061.64~22.04.1 - Upgrade
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ubuntu/linux-azure-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1063.71~22.04.1 - Upgrade
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ubuntu/linux-gcp-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1064.72~22.04.1 - Upgrade
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ubuntu/linux-hwe-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-136.136~22.04.1 - Upgrade
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ubuntu/linux-nvidia-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1059.62~22.04.1 - Upgrade
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ubuntu/linux-oracle-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1058.61~22.04.1 - Upgrade
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ubuntu/linux-realtime-6.8to a version that resolves this vulnerability.Fixed in 6.8.1-1056.57~22.04.2 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 6.8.0-1061.64 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 6.8.0-1064.72 - Upgrade
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ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 6.8.0-136.136.2 - Upgrade
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ubuntu/linux-nvidiato a version that resolves this vulnerability.Fixed in 6.8.0-1059.62 - Upgrade
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ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 6.8.0-1030.31 - Upgrade
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ubuntu/linux-xilinxto a version that resolves this vulnerability.Fixed in 6.8.0-1033.34 - Upgrade
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ubuntu/linux-bluefieldto a version that resolves this vulnerability.Fixed in 6.8.0-1028.33 - Upgrade
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ubuntu/linux-aws-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1061.64+fips1 - Upgrade
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ubuntu/linux-azure-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1063.71+fips2 - Upgrade
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ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1064.72+fips1 - Upgrade
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ubuntu/linux-nvidiato a version that resolves this vulnerability.Fixed in 7.0.0-1006.6
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Linux kernel systems using the USB gadget RNDIS function are relevant, particularly where the function is bound and unbound across gadget lifecycle cycles. The issue concerns the network device surviving after its gadget-device parent is destroyed.
How can I tell whether the affected lifecycle state has occurred?
Check the sysfs entry for the RNDIS network interface, such as /sys/class/net/usb0. An affected state can appear as a symlink into the gadget device tree whose target no longer exists, for example a link to a missing gadget.0/net/usb0 path.
What access is required and what is the stated security impact?
The CVSS vector indicates local access and low privileges are required, with no user interaction. It rates the impact as high availability impact, with no stated confidentiality or integrity impact.