{"cve":"CVE-2025-40090","nvd":{"published":"2025-10-30T10:15:33.537","modified":"2026-10-19T21:10:00.160","status":"Modified","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-674"],"references":["https://git.kernel.org/stable/c/1891abe832cbf5a11039e088766131d0f1642d02","https://git.kernel.org/stable/c/3412fbd81b46b9cfae013817b61d4bbd27e09e36","https://git.kernel.org/stable/c/4602b8cee1481dbb896182e5cb1e8cf12910e9e7","https://git.kernel.org/stable/c/5493571f4351f74e11db9943e98a07c56467cf7e","https://git.kernel.org/stable/c/88f170814fea74911ceab798a43cbd7c5599bed4"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2025-40090","score":0.00282,"percentile":0.20515,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}