Medium 5.5Published May 8, 2026

CVE-2026-43421usb: gadget: f_ncm: Fix net_device lifecycle with device_move

Updated under an hour ago (Oct 28, 2026, 7:30 AM ET)

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_ncm: Fix net_device lifecycle with device_move The network device outlived its parent gadget device during disconnection, resulting in dangling sysfs links and null pointer dereference problems. A prior attempt to solve this by removing SET_NETDEV_DEV entirely [1] was reverted due to power management ordering concerns and a NO-CARRIER regression. A subsequent attempt to defer net_device allocation to bind [2] broke 1:1 mapping between function instance and network device, making it impossible for configfs to report the resolved interface name. This results in a regression where the DHCP server fails on pmOS. Use device_move to reparent the net_device between the gadget device and /sys/devices/virtual/ across bind/unbind cycles. This preserves the network interface across USB reconnection, allowing the DHCP server to retain their binding. Introduce gether_attach_gadget()/gether_detach_gadget() helpers and use __free(detach_gadget) macro to undo attachment on bind failure. The bind_count ensures device_move executes only on the first bind. [1] https://lore.kernel.org/lkml/f2a4f9847617a0929d62025748384092e5f35cce.camel@crapouillou.net/ [2] https://lore.kernel.org/linux-usb/795ea759-7eaf-4f78-81f4-01ffbf2d7961@ixit.cz/

CVSS: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	40d133d7f542616cf9538508a372306e626a16e9 builds before 7c97366f5dac5255e60a317ffe3a5b18f3745547; 40d133d7f542616cf9538508a372306e626a16e9 builds before 36c41e9724c9a7a7cda37f5a4e9d94f25c8031c4; from 40d133d7f542616cf9538508a372306e626a16e9 before 93f116c3393a22acab96ad1bef12b2572eb80ca4; from 40d133d7f542616cf9538508a372306e626a16e9 before e584cb58a2ea7ff4d3a4bc43d5ca512ed3ecb77d; from 40d133d7f542616cf9538508a372306e626a16e9 before 85acaba2f42b557499bab3608307f17bf13beb69; from 40d133d7f542616cf9538508a372306e626a16e9 before ec35c1969650e7cb6c8a91020e568ed46e3551b0	CNA record
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name)	all versions	CISA ADP
linux linux_kernel linux:linux_kernel	from 3.11 before 6.12.78; from 6.13 before 6.18.19; from 6.19 before 6.19.9; 7.0; 7.0; 7.0	NVD

References

References

https://git.kernel.org/stable/c/7c97366f5dac5255e60a317ffe3a5b18f3745547
https://git.kernel.org/stable/c/36c41e9724c9a7a7cda37f5a4e9d94f25c8031c4
https://git.kernel.org/stable/c/93f116c3393a22acab96ad1bef12b2572eb80ca4	patch
https://git.kernel.org/stable/c/e584cb58a2ea7ff4d3a4bc43d5ca512ed3ecb77d	patch
https://git.kernel.org/stable/c/85acaba2f42b557499bab3608307f17bf13beb69	patch
https://git.kernel.org/stable/c/ec35c1969650e7cb6c8a91020e568ed46e3551b0	patch
https://cert-portal.siemens.com/productcert/html/ssa-784472.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.