7.8
/ 10
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Description
In the Linux kernel, the following vulnerability has been resolved:
tcp: call sk_data_ready() after listener migration
When inet_csk_listen_stop() migrates an established child socket from
a closing listener to another socket in the same SO_REUSEPORT group,
the target listener gets a new accept-queue entry via
inet_csk_reqsk_queue_add(), but that path never notifies the target
listener's waiters. A nonblocking accept() still works because it
checks the queue directly, but poll()/epoll_wait() waiters and
blocking accept() callers can also remain asleep indefinitely.
Call READ_ONCE(nsk->sk_data_ready)(nsk) after a successful migration
in inet_csk_listen_stop().
However, after inet_csk_reqsk_queue_add() succeeds, the ref acquired
in reuseport_migrate_sock() is effectively transferred to
nreq->rsk_listener. Another CPU can then dequeue nreq via accept()
or listener shutdown, hit reqsk_put(), and drop that listener ref.
Since listeners are SOCK_RCU_FREE, wrap the post-queue_add()
dereferences of nsk in rcu_read_lock()/rcu_read_unlock(), which also
covers the existing sock_net(nsk) access in that path.
The reqsk_timer_handler() path does not need the same changes for two
reasons: half-open requests become readable only after the final ACK,
where tcp_child_process() already wakes the listener; and once nreq is
visible via inet_ehash_insert(), the success path no longer touches
nsk directly.
tcp: call sk_data_ready() after listener migration
When inet_csk_listen_stop() migrates an established child socket from
a closing listener to another socket in the same SO_REUSEPORT group,
the target listener gets a new accept-queue entry via
inet_csk_reqsk_queue_add(), but that path never notifies the target
listener's waiters. A nonblocking accept() still works because it
checks the queue directly, but poll()/epoll_wait() waiters and
blocking accept() callers can also remain asleep indefinitely.
Call READ_ONCE(nsk->sk_data_ready)(nsk) after a successful migration
in inet_csk_listen_stop().
However, after inet_csk_reqsk_queue_add() succeeds, the ref acquired
in reuseport_migrate_sock() is effectively transferred to
nreq->rsk_listener. Another CPU can then dequeue nreq via accept()
or listener shutdown, hit reqsk_put(), and drop that listener ref.
Since listeners are SOCK_RCU_FREE, wrap the post-queue_add()
dereferences of nsk in rcu_read_lock()/rcu_read_unlock(), which also
covers the existing sock_net(nsk) access in that path.
The reqsk_timer_handler() path does not need the same changes for two
reasons: half-open requests become readable only after the final ACK,
where tcp_child_process() already wakes the listener; and once nreq is
visible via inet_ehash_insert(), the success path no longer touches
nsk directly.
Basic Information
ID
CVE-2026-46015
Source
Linux
Published
May 27, 2026 at 12:56
Modified
May 30, 2026 at 10:46
Affected Product
Vendor
Linux
Product
Linux
Version
54b92e84193749c9968aff2dd46e3b0f42643e18
Affected Versions
Linux Linux 54b92e84193749c9968aff2dd46e3b0f42643e18
Linux Linux 54b92e84193749c9968aff2dd46e3b0f42643e18
Linux Linux 54b92e84193749c9968aff2dd46e3b0f42643e18
Linux Linux 54b92e84193749c9968aff2dd46e3b0f42643e18
Linux Linux 54b92e84193749c9968aff2dd46e3b0f42643e18
Linux Linux 5.14
Linux Linux 54b92e84193749c9968aff2dd46e3b0f42643e18
Linux Linux 54b92e84193749c9968aff2dd46e3b0f42643e18
Linux Linux 54b92e84193749c9968aff2dd46e3b0f42643e18
Linux Linux 54b92e84193749c9968aff2dd46e3b0f42643e18
Linux Linux 5.14
References
- git.kernel.org /stable/c/ab5fdcd535645f6dbe6e9e21d96a08d141e88b4b
- git.kernel.org /stable/c/bebd058ef40c67a81fe6d9ee8beaa4ede90e0704
- git.kernel.org /stable/c/83bb57635d7cbafde32f865b577ecfd969f02337
- git.kernel.org /stable/c/12625b4da84caf4d84a04988710a7b9bcf702b18
- git.kernel.org /stable/c/3864c6ba1e041bc75342353a70fa2a2c6f909923