Description
In the Linux kernel, the following vulnerability has been resolved:
nfc: llcp: Fix race condition in accept_queue lifecycle
In nfc_llcp_socket_release(), sockets and listener accept queues are
walked under the local sockets rwlock and bh_lock_sock(). However,
bh_lock_sock() does not synchronise against process-context lock_sock()
held by nfc_llcp_accept_dequeue() during accept(). Because
socket_release() does not check sock_owned_by_user(), both paths can
concurrently unlink and release the same child socket, resulting in
use-after-free or a NULL pointer dereference of child->parent in
nfc_llcp_accept_unlink().
Fix this synchronisation race by having nfc_llcp_socket_release() use
process-context lock_sock() instead of bh_lock_sock():
1. Pop sockets from the local sockets list under the write lock using
nfc_llcp_sock_list_pop() so lock_sock() can be acquired without
holding the rwlock.
2. Because lock_sock() can sleep, defer the final release of the
nfc_llcp_local structure to a workqueue (release_work). This avoids
a sleeping-in-atomic bug when the last local reference is dropped
from softirq context. Additionally, hold a single device reference
on local from registration until final destruction.
3. In nfc_llcp_local_get(), use kref_get_unless_zero() to prevent
resurrecting a local object whose teardown has been scheduled.
4. In llcp_sock_accept(), verify that the listener socket state is still
LLCP_LISTEN after waking from schedule_timeout() to prevent hangs if
the listener is closed concurrently.
5. When unlinking unaccepted child sockets during listener release,
unlink them from local->sockets, call sock_orphan(), and drop their
initial sk_alloc creation reference via sock_put().
6. Make nfc_llcp_accept_unlink() idempotent by guarding parent access with
a NULL check.
nfc: llcp: Fix race condition in accept_queue lifecycle
In nfc_llcp_socket_release(), sockets and listener accept queues are
walked under the local sockets rwlock and bh_lock_sock(). However,
bh_lock_sock() does not synchronise against process-context lock_sock()
held by nfc_llcp_accept_dequeue() during accept(). Because
socket_release() does not check sock_owned_by_user(), both paths can
concurrently unlink and release the same child socket, resulting in
use-after-free or a NULL pointer dereference of child->parent in
nfc_llcp_accept_unlink().
Fix this synchronisation race by having nfc_llcp_socket_release() use
process-context lock_sock() instead of bh_lock_sock():
1. Pop sockets from the local sockets list under the write lock using
nfc_llcp_sock_list_pop() so lock_sock() can be acquired without
holding the rwlock.
2. Because lock_sock() can sleep, defer the final release of the
nfc_llcp_local structure to a workqueue (release_work). This avoids
a sleeping-in-atomic bug when the last local reference is dropped
from softirq context. Additionally, hold a single device reference
on local from registration until final destruction.
3. In nfc_llcp_local_get(), use kref_get_unless_zero() to prevent
resurrecting a local object whose teardown has been scheduled.
4. In llcp_sock_accept(), verify that the listener socket state is still
LLCP_LISTEN after waking from schedule_timeout() to prevent hangs if
the listener is closed concurrently.
5. When unlinking unaccepted child sockets during listener release,
unlink them from local->sockets, call sock_orphan(), and drop their
initial sk_alloc creation reference via sock_put().
6. Make nfc_llcp_accept_unlink() idempotent by guarding parent access with
a NULL check.
Published:
2026-10-18
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
No analysis available yet.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
|
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No data available yet.
Remediation
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References
History
Sun, 18 Oct 2026 15:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: nfc: llcp: Fix race condition in accept_queue lifecycle In nfc_llcp_socket_release(), sockets and listener accept queues are walked under the local sockets rwlock and bh_lock_sock(). However, bh_lock_sock() does not synchronise against process-context lock_sock() held by nfc_llcp_accept_dequeue() during accept(). Because socket_release() does not check sock_owned_by_user(), both paths can concurrently unlink and release the same child socket, resulting in use-after-free or a NULL pointer dereference of child->parent in nfc_llcp_accept_unlink(). Fix this synchronisation race by having nfc_llcp_socket_release() use process-context lock_sock() instead of bh_lock_sock(): 1. Pop sockets from the local sockets list under the write lock using nfc_llcp_sock_list_pop() so lock_sock() can be acquired without holding the rwlock. 2. Because lock_sock() can sleep, defer the final release of the nfc_llcp_local structure to a workqueue (release_work). This avoids a sleeping-in-atomic bug when the last local reference is dropped from softirq context. Additionally, hold a single device reference on local from registration until final destruction. 3. In nfc_llcp_local_get(), use kref_get_unless_zero() to prevent resurrecting a local object whose teardown has been scheduled. 4. In llcp_sock_accept(), verify that the listener socket state is still LLCP_LISTEN after waking from schedule_timeout() to prevent hangs if the listener is closed concurrently. 5. When unlinking unaccepted child sockets during listener release, unlink them from local->sockets, call sock_orphan(), and drop their initial sk_alloc creation reference via sock_put(). 6. Make nfc_llcp_accept_unlink() idempotent by guarding parent access with a NULL check. | |
| Title | nfc: llcp: Fix race condition in accept_queue lifecycle | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-18T15:18:53.819Z
Reserved: 2026-09-25T10:25:14.358Z
Link: CVE-2026-98580
Vulnrichment
No data.
NVD
No data.
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.