Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
Linux Linux — ksmbd: fix recursive locking in RPC handle list access
AV AC PR UI S C I A CVSS EPSS %ile KEV
L L L N U N N H 5.5 .0026 18.0 —
AFFECTED
Product Versions Fixed
Linux 69674b029002b1d90b655f014bdf64f404efa54d – —
Linux 6.12.53 – —
TIMELINE
Apr 16 Reserved by Linux
Oct 30 Published (CNA: Linux)
Jul 30 RESCORED — CVE-2025-40090 (Linux). CVSS 7.5 → 5.5 (NVD).
Description
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix recursive locking in RPC handle list access
Since commit 305853cce3794 ("ksmbd: Fix race condition in RPC handle list
access"), ksmbd_session_rpc_method() attempts to lock sess->rpc_lock.
This causes hung connections / tasks when a client attempts to open
a named pipe. Using Samba's rpcclient tool:
$ rpcclient //192.168.1.254 -U user%password
$ rpcclient $> srvinfo
<connection hung here>
Kernel side:
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:0 state:D stack:0 pid:5021 tgid:5021 ppid:2 flags:0x00200000
Workqueue: ksmbd-io handle_ksmbd_work
Call trace:
__schedule from schedule+0x3c/0x58
schedule from schedule_preempt_disabled+0xc/0x10
schedule_preempt_disabled from rwsem_down_read_slowpath+0x1b0/0x1d8
rwsem_down_read_slowpath from down_read+0x28/0x30
down_read from ksmbd_session_rpc_method+0x18/0x3c
ksmbd_session_rpc_method from ksmbd_rpc_open+0x34/0x68
ksmbd_rpc_open from ksmbd_session_rpc_open+0x194/0x228
ksmbd_session_rpc_open from create_smb2_pipe+0x8c/0x2c8
create_smb2_pipe from smb2_open+0x10c/0x27ac
smb2_open from handle_ksmbd_work+0x238/0x3dc
handle_ksmbd_work from process_scheduled_works+0x160/0x25c
process_scheduled_works from worker_thread+0x16c/0x1e8
worker_thread from kthread+0xa8/0xb8
kthread from ret_from_fork+0x14/0x38
Exception stack(0x8529ffb0 to 0x8529fff8)
The task deadlocks because the lock is already held:
ksmbd_session_rpc_open
down_write(&sess->rpc_lock)
ksmbd_rpc_open
ksmbd_session_rpc_method
down_read(&sess->rpc_lock) <-- deadlock
Adjust ksmbd_session_rpc_method() callers to take the lock when necessary.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
| April 16, 2025 | Reserved | Reserved by Linux |
| October 30, 2025 | Published | Published (CNA: Linux) |
| July 30, 2026 | RESCORED | RESCORED — CVE-2025-40090 (Linux). CVSS 7.5 → 5.5 (NVD). |
Affected
Affected products and packages — 2 rows
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
| Linux | Linux | — | 69674b029002b1d90b655f014bdf64f404efa54d | — |
| Linux | Linux | — | 6.12.53 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2025-40090 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.