{"id":"CVE-2026-43421","state":"PUBLISHED","title":"usb: gadget: f_ncm: Fix net_device lifecycle with device_move","description":"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/","publishedAt":"2026-05-08T14:21:56.363Z","updatedAt":"2026-10-15T01:19:23.793Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"40d133d7f542616cf9538508a372306e626a16e9","status":"affected","lessThan":"7c97366f5dac5255e60a317ffe3a5b18f3745547","versionType":"git"},{"version":"40d133d7f542616cf9538508a372306e626a16e9","status":"affected","lessThan":"36c41e9724c9a7a7cda37f5a4e9d94f25c8031c4","versionType":"git"},{"version":"40d133d7f542616cf9538508a372306e626a16e9","status":"affected","lessThan":"93f116c3393a22acab96ad1bef12b2572eb80ca4","versionType":"git"},{"version":"40d133d7f542616cf9538508a372306e626a16e9","status":"affected","lessThan":"e584cb58a2ea7ff4d3a4bc43d5ca512ed3ecb77d","versionType":"git"},{"version":"40d133d7f542616cf9538508a372306e626a16e9","status":"affected","lessThan":"85acaba2f42b557499bab3608307f17bf13beb69","versionType":"git"},{"version":"40d133d7f542616cf9538508a372306e626a16e9","status":"affected","lessThan":"ec35c1969650e7cb6c8a91020e568ed46e3551b0","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_ncm.c","drivers/usb/gadget/function/u_ether.c","drivers/usb/gadget/function/u_ether.h","drivers/usb/gadget/function/u_ncm.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.11","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.11","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.78","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.19","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.9","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_ncm.c","drivers/usb/gadget/function/u_ether.c","drivers/usb/gadget/function/u_ether.h","drivers/usb/gadget/function/u_ncm.h"]}],"references":["https://git.kernel.org/stable/c/7c97366f5dac5255e60a317ffe3a5b18f3745547","https://git.kernel.org/stable/c/36c41e9724c9a7a7cda37f5a4e9d94f25c8031c4","https://git.kernel.org/stable/c/93f116c3393a22acab96ad1bef12b2572eb80ca4","https://git.kernel.org/stable/c/e584cb58a2ea7ff4d3a4bc43d5ca512ed3ecb77d","https://git.kernel.org/stable/c/85acaba2f42b557499bab3608307f17bf13beb69","https://git.kernel.org/stable/c/ec35c1969650e7cb6c8a91020e568ed46e3551b0","https://cert-portal.siemens.com/productcert/html/ssa-784472.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/43xxx/CVE-2026-43421.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-43421","state":"PUBLISHED","datePublished":"2026-05-08T14:21:56.363Z","dateUpdated":"2026-10-15T01:19:23.793Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-01T14:12:56.008Z"},"containers":{"cna":{"title":"usb: gadget: f_ncm: Fix net_device lifecycle with device_move","descriptions":[{"lang":"en","value":"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/"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"40d133d7f542616cf9538508a372306e626a16e9","status":"affected","lessThan":"7c97366f5dac5255e60a317ffe3a5b18f3745547","versionType":"git"},{"version":"40d133d7f542616cf9538508a372306e626a16e9","status":"affected","lessThan":"36c41e9724c9a7a7cda37f5a4e9d94f25c8031c4","versionType":"git"},{"version":"40d133d7f542616cf9538508a372306e626a16e9","status":"affected","lessThan":"93f116c3393a22acab96ad1bef12b2572eb80ca4","versionType":"git"},{"version":"40d133d7f542616cf9538508a372306e626a16e9","status":"affected","lessThan":"e584cb58a2ea7ff4d3a4bc43d5ca512ed3ecb77d","versionType":"git"},{"version":"40d133d7f542616cf9538508a372306e626a16e9","status":"affected","lessThan":"85acaba2f42b557499bab3608307f17bf13beb69","versionType":"git"},{"version":"40d133d7f542616cf9538508a372306e626a16e9","status":"affected","lessThan":"ec35c1969650e7cb6c8a91020e568ed46e3551b0","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_ncm.c","drivers/usb/gadget/function/u_ether.c","drivers/usb/gadget/function/u_ether.h","drivers/usb/gadget/function/u_ncm.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.11","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.11","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.78","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.19","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.9","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_ncm.c","drivers/usb/gadget/function/u_ether.c","drivers/usb/gadget/function/u_ether.h","drivers/usb/gadget/function/u_ncm.h"]}],"references":[{"url":"https://git.kernel.org/stable/c/7c97366f5dac5255e60a317ffe3a5b18f3745547"},{"url":"https://git.kernel.org/stable/c/36c41e9724c9a7a7cda37f5a4e9d94f25c8031c4"},{"url":"https://git.kernel.org/stable/c/93f116c3393a22acab96ad1bef12b2572eb80ca4"},{"url":"https://git.kernel.org/stable/c/e584cb58a2ea7ff4d3a4bc43d5ca512ed3ecb77d"},{"url":"https://git.kernel.org/stable/c/85acaba2f42b557499bab3608307f17bf13beb69"},{"url":"https://git.kernel.org/stable/c/ec35c1969650e7cb6c8a91020e568ed46e3551b0"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-06-19T11:58:36.714Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.11","versionEndExcluding":"6.1.176"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.11","versionEndExcluding":"6.6.143"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.11","versionEndExcluding":"6.12.78"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.11","versionEndExcluding":"6.18.19"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.11","versionEndExcluding":"6.19.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.11","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"affected":[{"vendor":"Siemens","product":"SIMATIC S7-1500 TM MFP - GNU/Linux subsystem","defaultStatus":"unknown","versions":[{"version":"0","status":"affected","lessThan":"*","versionType":"custom"}]}],"references":[{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html"}],"providerMetadata":{"shortName":"siemens-SADP","orgId":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","dateUpdated":"2026-10-15T01:19:23.793Z"},"x_adpType":"supplier"}]}}}