CVE-2026-31727
Analyzed Analyzed - Analysis Complete
NULL Pointer Dereference in Linux Kernel USB Gadget

Publication date: 2026-05-01

Last updated on: 2026-05-07

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: u_ether: Fix NULL pointer deref in eth_get_drvinfo Commit ec35c1969650 ("usb: gadget: f_ncm: Fix net_device lifecycle with device_move") reparents the gadget device to /sys/devices/virtual during unbind, clearing the gadget pointer. If the userspace tool queries on the surviving interface during this detached window, this leads to a NULL pointer dereference. Unable to handle kernel NULL pointer dereference Call trace: eth_get_drvinfo+0x50/0x90 ethtool_get_drvinfo+0x5c/0x1f0 __dev_ethtool+0xaec/0x1fe0 dev_ethtool+0x134/0x2e0 dev_ioctl+0x338/0x560 Add a NULL check for dev->gadget in eth_get_drvinfo(). When detached, skip copying the fw_version and bus_info strings, which is natively handled by ethtool_get_drvinfo for empty strings.
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Meta Information
Published
2026-05-01
Last Modified
2026-05-07
Generated
2026-06-16
AI Q&A
2026-05-01
EPSS Evaluated
2026-06-15
NVD
CVE-2026-31727
EUVD
EUVD-2026-26540
Affected Vendors & Products
Showing 9 associated CPEs
Vendor Product Version / Range
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel From 6.12.78 (inc) to 6.12.81 (exc)
linux linux_kernel From 6.18.19 (inc) to 6.18.22 (exc)
linux linux_kernel From 6.19.9 (inc) to 6.19.12 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-476 The product dereferences a pointer that it expects to be valid but is NULL.
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Executive Summary

This vulnerability exists in the Linux kernel's USB gadget subsystem, specifically in the u_ether driver. It occurs because after a gadget device is unbound and reparented to a different location in the device hierarchy, a userspace tool querying the network interface during this detached state can trigger a NULL pointer dereference.

The issue arises when the eth_get_drvinfo function attempts to access the gadget pointer, which may be NULL during this window, leading to a kernel crash. The fix involves adding a NULL check for the gadget pointer in eth_get_drvinfo to safely skip copying certain strings when the device is detached.

Impact Analysis

This vulnerability can cause a kernel NULL pointer dereference, which typically results in a kernel crash or system instability. If exploited or triggered, it could lead to denial of service by crashing the affected system or device running the vulnerable Linux kernel.

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