CVE-2026-98580 nfc: llcp: Fix race condition in accept_queue lifecycle
A race condition in the Linux kernel NFC LLCP subsystem allows concurrent socket release, leading to use-after-free or NULL dereference, potentially causing crashes or code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98580?
CVE-2026-98580 is a vulnerability in Linux, published on 18 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-98580?
How do I fix CVE-2026-98580?
Apply the vendor's patch.
Is CVE-2026-98580 being exploited?
There is no known exploitation of CVE-2026-98580 in the wild and no public exploit code.
Sources
Also known as AZL-109194, BELL-CVE-2026-98580, DEBIAN-CVE-2026-98580, GHSA-f48w-jg7j-gjm2, UBUNTU-CVE-2026-98580.