CVE-2025-40090

Estado: ModificadaMedia (5.5)—

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>

Adjust ksmbd_session_rpc_method() callers to take the lock when necessary.

Detalles técnicos trazas, registros y código del informe original

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

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 5.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.28%
Percentil entre todas las CVEs puntuadas: 19
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)

Linux — Linux Kernel

CWE

CWE-674

Referencias

JSON original (NVD)

Mostrar

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix recursive locking in RPC handle list access\n\nSince commit 305853cce3794 (\"ksmbd: Fix race condition in RPC handle list\naccess\"), ksmbd_session_rpc_method() attempts to lock sess->rpc_lock.\n\nThis causes hung connections / tasks when a client attempts to open\na named pipe. Using Samba's rpcclient tool:\n\n $ rpcclient //192.168.1.254 -U user%password\n $ rpcclient $> srvinfo\n <connection hung here>\n\nKernel side:\n  \"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\" disables this message.\n  task:kworker/0:0 state:D stack:0 pid:5021 tgid:5021 ppid:2 flags:0x00200000\n  Workqueue: ksmbd-io handle_ksmbd_work\n  Call trace:\n  __schedule from schedule+0x3c/0x58\n  schedule from schedule_preempt_disabled+0xc/0x10\n  schedule_preempt_disabled from rwsem_down_read_slowpath+0x1b0/0x1d8\n  rwsem_down_read_slowpath from down_read+0x28/0x30\n  down_read from ksmbd_session_rpc_method+0x18/0x3c\n  ksmbd_session_rpc_method from ksmbd_rpc_open+0x34/0x68\n  ksmbd_rpc_open from ksmbd_session_rpc_open+0x194/0x228\n  ksmbd_session_rpc_open from create_smb2_pipe+0x8c/0x2c8\n  create_smb2_pipe from smb2_open+0x10c/0x27ac\n  smb2_open from handle_ksmbd_work+0x238/0x3dc\n  handle_ksmbd_work from process_scheduled_works+0x160/0x25c\n  process_scheduled_works from worker_thread+0x16c/0x1e8\n  worker_thread from kthread+0xa8/0xb8\n  kthread from ret_from_fork+0x14/0x38\n  Exception stack(0x8529ffb0 to 0x8529fff8)\n\nThe task deadlocks because the lock is already held:\n  ksmbd_session_rpc_open\n    down_write(&sess->rpc_lock)\n    ksmbd_rpc_open\n      ksmbd_session_rpc_method\n        down_read(&sess->rpc_lock)   <-- deadlock\n\nAdjust ksmbd_session_rpc_method() callers to take the lock when necessary."
    }
  ],
  "lastModified": "2026-07-30T06:24:10.810",
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