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CVE-2026-43421 (GCVE-0-2026-43421)

Vulnerability from cvelistv5 – Published: 2026-05-08 14:21 – Updated: 2026-06-19 11:58
VLAI
Title
usb: gadget: f_ncm: Fix net_device lifecycle with device_move
Summary
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/
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 40d133d7f542616cf9538508a372306e626a16e9 , < 7c97366f5dac5255e60a317ffe3a5b18f3745547 (git)
Affected: 40d133d7f542616cf9538508a372306e626a16e9 , < 36c41e9724c9a7a7cda37f5a4e9d94f25c8031c4 (git)
Affected: 40d133d7f542616cf9538508a372306e626a16e9 , < 93f116c3393a22acab96ad1bef12b2572eb80ca4 (git)
Affected: 40d133d7f542616cf9538508a372306e626a16e9 , < e584cb58a2ea7ff4d3a4bc43d5ca512ed3ecb77d (git)
Affected: 40d133d7f542616cf9538508a372306e626a16e9 , < 85acaba2f42b557499bab3608307f17bf13beb69 (git)
Affected: 40d133d7f542616cf9538508a372306e626a16e9 , < ec35c1969650e7cb6c8a91020e568ed46e3551b0 (git)
guessed Create a notification for this product.
Linux Linux Affected: 3.11
Unaffected: 0 , < 3.11 (semver)
Unaffected: 6.1.176 , ≤ 6.1.* (semver)
Unaffected: 6.6.143 , ≤ 6.6.* (semver)
Unaffected: 6.12.78 , ≤ 6.12.* (semver)
Unaffected: 6.18.19 , ≤ 6.18.* (semver)
Unaffected: 6.19.9 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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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. 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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-02T12:47:00+00:00",
      "cve": "CVE-2026-43421",
      "id": "CVE-2026-43421",
      "initial_release_date": "2026-05-08T00:00:00+00:00",
      "product_status:known_affected": "76",
      "product_status:known_not_affected": "198",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: usb: gadget: f_ncm: Fix net_device lifecycle with device_move",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43421.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-12T16:35:50Z",
      "cve": "CVE-2026-43421",
      "id": "CVE-2026-43421",
      "initial_release_date": "2026-05-13T03:34:10Z",
      "product_status:known_affected": "57",
      "product_status:known_not_affected": "36",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-43421",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-43421.json",
      "version": "4"
    }
  }
}



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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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