GHSA-9V5W-7XMR-346P
Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-22 18:30In the Linux kernel, the following vulnerability has been resolved:
net: usb: ipheth: fix carrier_work UAF on disconnect
ipheth_sndbulk_callback() re-arms the carrier-check work on any non-zero URB status:
else
schedule_delayed_work(&dev->carrier_work, 0);
Nothing ties that to the interface being up, so the work can be armed again after ipheth_close() has already drained it, and stay armed until the netdev whose private area embeds it is freed.
On unplug with a TX URB in flight, ipheth_disconnect() drains the work through unregister_netdev() -> ipheth_close() -> cancel_delayed_work_sync() and only then calls ipheth_kill_urbs(). usb_kill_urb() completes the in-flight TX URB with -ENOENT, so ipheth_sndbulk_callback() runs after the drain and re-arms carrier_work.
The same completion also re-arms the work if the interface is only brought down while a TX URB is in flight, and ipheth_carrier_check_work() then keeps re-queueing itself once a second. unregister_netdev() does not call ipheth_close() for an already-down interface, so nothing drains it on the later unplug either.
In both cases free_netdev() frees the netdev while carrier_work is still pending, and ipheth_carrier_check_work() dereferences freed memory.
Tie the work to the interface state instead of chasing the completion: disable it in ipheth_close() and enable it in ipheth_open(), so a schedule_delayed_work() from the URB completion is a no-op whenever the interface is not up. disable_delayed_work_sync() also waits for a running instance, so it fully replaces the cancel_delayed_work_sync() it takes the place of. The work starts out disabled in ipheth_probe() so the enable/disable counts balance from the first open.
Reproduced under KASAN on linux-next (next-20260731) with dummy_hcd and raw-gadget standing in for the device, driving the second path above (the interface is already down, so unregister_netdev() does not call ipheth_close()): 15 of 15 unpatched boots report a slab-use-after-free in __run_timers(), freed by ipheth_disconnect() and re-armed from ipheth_sndbulk_callback() via queue_delayed_work_on(). The same trigger on a kernel differing only by this patch reports 0 of 15, and the carrier check still functions across open/close cycles.
The reproducer needs an attached USB device that stops draining bulk OUT, plus a link down and unplug, driven as root. It is not a privilege boundary crossing and no exploit primitive was developed.
Found by 0sec (https://0sec.ai).
{
"affected": [],
"aliases": [
"CVE-2026-74677"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-22T16:16:41Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: usb: ipheth: fix carrier_work UAF on disconnect\n\nipheth_sndbulk_callback() re-arms the carrier-check work on any\nnon-zero URB status:\n\n\telse\n\t\tschedule_delayed_work(\u0026dev-\u003ecarrier_work, 0);\n\nNothing ties that to the interface being up, so the work can be armed\nagain after ipheth_close() has already drained it, and stay armed\nuntil the netdev whose private area embeds it is freed.\n\nOn unplug with a TX URB in flight, ipheth_disconnect() drains the work\nthrough unregister_netdev() -\u003e ipheth_close() -\u003e\ncancel_delayed_work_sync() and only then calls ipheth_kill_urbs().\nusb_kill_urb() completes the in-flight TX URB with -ENOENT, so\nipheth_sndbulk_callback() runs after the drain and re-arms\ncarrier_work.\n\nThe same completion also re-arms the work if the interface is only\nbrought down while a TX URB is in flight, and\nipheth_carrier_check_work() then keeps re-queueing itself once a\nsecond. unregister_netdev() does not call ipheth_close() for an\nalready-down interface, so nothing drains it on the later unplug\neither.\n\nIn both cases free_netdev() frees the netdev while carrier_work is\nstill pending, and ipheth_carrier_check_work() dereferences freed\nmemory.\n\nTie the work to the interface state instead of chasing the completion:\ndisable it in ipheth_close() and enable it in ipheth_open(), so a\nschedule_delayed_work() from the URB completion is a no-op whenever\nthe interface is not up. disable_delayed_work_sync() also waits for a\nrunning instance, so it fully replaces the cancel_delayed_work_sync()\nit takes the place of. The work starts out disabled in ipheth_probe()\nso the enable/disable counts balance from the first open.\n\nReproduced under KASAN on linux-next (next-20260731) with dummy_hcd and\nraw-gadget standing in for the device, driving the second path above (the\ninterface is already down, so unregister_netdev() does not call\nipheth_close()): 15 of 15 unpatched boots report a slab-use-after-free in\n__run_timers(), freed by ipheth_disconnect() and re-armed from\nipheth_sndbulk_callback() via queue_delayed_work_on(). The\nsame trigger on a kernel differing only by this patch reports 0 of 15,\nand the carrier check still functions across open/close cycles.\n\nThe reproducer needs an attached USB device that stops draining bulk OUT,\nplus a link down and unplug, driven as root. It is not a privilege\nboundary crossing and no exploit primitive was developed.\n\nFound by 0sec (https://0sec.ai).",
"id": "GHSA-9v5w-7xmr-346p",
"modified": "2026-08-22T18:30:29Z",
"published": "2026-08-22T18:30:28Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74677"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2c7496124e94c7f9c3daa5c5b1fb563ca9d62c45"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/48303f3ae0fa6e102f3fc7dbf1688cc179131962"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d07133fe1befae9a1e4c4c5e46ef0b73d2992020"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fde39b8a521780391fb4e5bda2c0aa4928947f12"
}
],
"schema_version": "1.4.0",
"severity": []
}
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