{"id":"CVE-2026-43421","summary":"usb: gadget: f_ncm: Fix net_device lifecycle with device_move","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_ncm: Fix net_device lifecycle with device_move\n\nThe network device outlived its parent gadget device during\ndisconnection, resulting in dangling sysfs links and null pointer\ndereference problems.\n\nA prior attempt to solve this by removing SET_NETDEV_DEV entirely [1]\nwas reverted due to power management ordering concerns and a NO-CARRIER\nregression.\n\nA subsequent attempt to defer net_device allocation to bind [2] broke\n1:1 mapping between function instance and network device, making it\nimpossible for configfs to report the resolved interface name. This\nresults in a regression where the DHCP server fails on pmOS.\n\nUse device_move to reparent the net_device between the gadget device and\n/sys/devices/virtual/ across bind/unbind cycles. This preserves the\nnetwork interface across USB reconnection, allowing the DHCP server to\nretain their binding.\n\nIntroduce gether_attach_gadget()/gether_detach_gadget() helpers and use\n__free(detach_gadget) macro to undo attachment on bind failure. The\nbind_count ensures device_move executes only on the first bind.\n\n[1] https://lore.kernel.org/lkml/f2a4f9847617a0929d62025748384092e5f35cce.camel@crapouillou.net/\n[2] https://lore.kernel.org/linux-usb/795ea759-7eaf-4f78-81f4-01ffbf2d7961@ixit.cz/","modified":"2026-07-15T01:48:58.925814049Z","published":"2026-05-08T14:21:56.363Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43421.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/36c41e9724c9a7a7cda37f5a4e9d94f25c8031c4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7c97366f5dac5255e60a317ffe3a5b18f3745547"},{"type":"WEB","url":"https://git.kernel.org/stable/c/85acaba2f42b557499bab3608307f17bf13beb69"},{"type":"WEB","url":"https://git.kernel.org/stable/c/93f116c3393a22acab96ad1bef12b2572eb80ca4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e584cb58a2ea7ff4d3a4bc43d5ca512ed3ecb77d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ec35c1969650e7cb6c8a91020e568ed46e3551b0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43421.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43421"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"40d133d7f542616cf9538508a372306e626a16e9"},{"fixed":"7c97366f5dac5255e60a317ffe3a5b18f3745547"},{"fixed":"36c41e9724c9a7a7cda37f5a4e9d94f25c8031c4"},{"fixed":"93f116c3393a22acab96ad1bef12b2572eb80ca4"},{"fixed":"e584cb58a2ea7ff4d3a4bc43d5ca512ed3ecb77d"},{"fixed":"85acaba2f42b557499bab3608307f17bf13beb69"},{"fixed":"ec35c1969650e7cb6c8a91020e568ed46e3551b0"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43421.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.11.0"},{"fixed":"6.1.176"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.143"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.78"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.19"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43421.json"}}],"schema_version":"1.7.5"}