CVE-2026-97975
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_sysfs: Fix NULL pointer dereference in device_del()
A NULL pointer dereference in klist_put() occurs when a child device (such as a BNEP network device in bnep_session) is concurrently being unregistered while hci_conn_del_sysfs() reparents child devices.
This is caused by a race condition between hci_conn_del_sysfs() and concurrent child device unregistration (e.g. bnep_session calling unregister_netdev()). During device unregistration, device_del() snapshots a non-NULL parent pointer.
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Concurrently, hci_conn_del_sysfs() finds the child device using device_find_any_child() and calls device_move() to reparent it to NULL, which removes the node from its parent's klist and clears knode_parent. Subsequently, device_del() calls klist_del(&dev->p->knode_parent) using the stale parent snapshot, causing klist_put() to dereference knode_klist(n)->put on an already removed node, resulting in a NULL pointer dereference.
This race was introduced by commit 27aabf27fd01 ("Bluetooth: fix use-after-free in device_for_each_child()"), which replaced device_find_child(..., __match_tty) with device_find_any_child() in hci_conn_del_sysfs(). That change was intended to avoid a use-after-free where conn->dev outlived its parent hdev->dev when child devices held references to conn->dev, because conn->dev only held a reference to hdev->dev while registered in sysfs.
Fix the issue properly by taking an explicit reference to the parent device with get_device(&hdev->dev) in hci_conn_init_sysfs() and dropping it with put_device(parent) in bt_link_release() when the conn device is freed. This ensures that hdev->dev remains valid for the entire lifecycle of conn->dev, resolving the underlying use-after-free. With the parent reference held properly, restore the __match_tty filter in hci_conn_del_sysfs() so that device_move() is only invoked on persistent RFCOMM TTY devices as originally intended, eliminating the race condition with unregistering network devices.
CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.17%
- Percentil entre todas las CVEs puntuadas: 5
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
JSON original (NVD)
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{
"id": "CVE-2026-97975",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"published": "2026-09-25T11:17:25.427",
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"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sysfs: Fix NULL pointer dereference in device_del()\n\nA NULL pointer dereference in klist_put() occurs when a child device (such\nas a BNEP network device in bnep_session) is concurrently being\nunregistered while hci_conn_del_sysfs() reparents child devices.\n\nThis is caused by a race condition between hci_conn_del_sysfs() and\nconcurrent child device unregistration (e.g. bnep_session calling\nunregister_netdev()). During device unregistration, device_del() snapshots\na non-NULL parent pointer. Concurrently, hci_conn_del_sysfs() finds the\nchild device using device_find_any_child() and calls device_move() to\nreparent it to NULL, which removes the node from its parent's klist and\nclears knode_parent. Subsequently, device_del() calls\nklist_del(&dev->p->knode_parent) using the stale parent snapshot, causing\nklist_put() to dereference knode_klist(n)->put on an already removed node,\nresulting in a NULL pointer dereference.\n\nThis race was introduced by commit 27aabf27fd01 (\"Bluetooth: fix\nuse-after-free in device_for_each_child()\"), which replaced\ndevice_find_child(..., __match_tty) with device_find_any_child() in\nhci_conn_del_sysfs(). That change was intended to avoid a use-after-free\nwhere conn->dev outlived its parent hdev->dev when child devices held\nreferences to conn->dev, because conn->dev only held a reference to\nhdev->dev while registered in sysfs.\n\nFix the issue properly by taking an explicit reference to the parent device\nwith get_device(&hdev->dev) in hci_conn_init_sysfs() and dropping it with\nput_device(parent) in bt_link_release() when the conn device is freed. This\nensures that hdev->dev remains valid for the entire lifecycle of conn->dev,\nresolving the underlying use-after-free. With the parent reference held\nproperly, restore the __match_tty filter in hci_conn_del_sysfs() so that\ndevice_move() is only invoked on persistent RFCOMM TTY devices as\noriginally intended, eliminating the race condition with unregistering\nnetwork devices."
}
],
"lastModified": "2026-09-25T11:17:25.427",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}