{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40090", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.162Z", "datePublished": "2025-10-30T09:47:58.611Z", "dateUpdated": "2026-08-05T12:07:42.312Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:07:42.312Z" }, "descriptions": [ { "lang": "en", "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 $> srvinfo\n \n\nKernel side:\n \"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\" disables this message.\n task:kworker/0:0 state:D stack:0 pid:5021 tgid:5021 ppid:2 flags:0x00200000\n Workqueue: ksmbd-io handle_ksmbd_work\n Call trace:\n __schedule from schedule+0x3c/0x58\n schedule from schedule_preempt_disabled+0xc/0x10\n schedule_preempt_disabled from rwsem_down_read_slowpath+0x1b0/0x1d8\n rwsem_down_read_slowpath from down_read+0x28/0x30\n down_read from ksmbd_session_rpc_method+0x18/0x3c\n ksmbd_session_rpc_method from ksmbd_rpc_open+0x34/0x68\n ksmbd_rpc_open from ksmbd_session_rpc_open+0x194/0x228\n ksmbd_session_rpc_open from create_smb2_pipe+0x8c/0x2c8\n create_smb2_pipe from smb2_open+0x10c/0x27ac\n smb2_open from handle_ksmbd_work+0x238/0x3dc\n handle_ksmbd_work from process_scheduled_works+0x160/0x25c\n process_scheduled_works from worker_thread+0x16c/0x1e8\n worker_thread from kthread+0xa8/0xb8\n kthread from ret_from_fork+0x14/0x38\n Exception stack(0x8529ffb0 to 0x8529fff8)\n\nThe task deadlocks because the lock is already held:\n ksmbd_session_rpc_open\n down_write(&sess->rpc_lock)\n ksmbd_rpc_open\n ksmbd_session_rpc_method\n down_read(&sess->rpc_lock) <-- deadlock\n\nAdjust ksmbd_session_rpc_method() callers to take the lock when necessary." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - ksmbd is the in-kernel SMB server listening on TCP/445, and the deadlock is triggered by a remote client sending an SMB2 CREATE for a named pipe on the IPC$ tree. No local access is needed.\nAC:L - This is an unconditional self-deadlock on a non-recursive rw_semaphore, hit deterministically on the very first named-pipe open — no race to win, no memory layout or timing dependency.\nPR:N - In the guest-mapping configuration common on ksmbd's NAS/embedded targets, ntlm_authenticate() skips NTLM password verification entirely for guest users, so an attacker with no credentials can establish a session, tree-connect to the always-present IPC$ share, and reach create_smb2_pipe().\nUI:N - The attacker triggers the deadlock purely by sending SMB2 protocol messages; no action by any local user or administrator is required.\nS:U - The deadlock affects kernel worker threads and ksmbd's own locks within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:N - The thread blocks in down_read() before doing anything else; no memory is freed, over-read, or leaked, and no data is disclosed to the attacker.\nI:N - No memory corruption or data modification occurs — the only effect is a permanently held lock, which yields no write primitive.\nA:H - An unkillable D-state kworker holds sess->rpc_lock forever, blocking connection teardown and — via ksmbd_sessions_deregister() holding the global sessions_table_lock — all sessions server-wide; destroy_workqueue() also hangs, so ksmbd cannot be restarted or unloaded and recovery requires a reboot." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/mgmt/user_session.c", "fs/smb/server/smb2pdu.c", "fs/smb/server/transport_ipc.c" ], "versions": [ { "version": "69674b029002b1d90b655f014bdf64f404efa54d", "lessThan": "5493571f4351f74e11db9943e98a07c56467cf7e", "status": "affected", "versionType": "git" }, { "version": "6b615a8fb3af0baf8126cde3d4fee97d57222ffc", "lessThan": "1891abe832cbf5a11039e088766131d0f1642d02", "status": "affected", "versionType": "git" }, { "version": "5cc679ba0f4505936124cd4179ba66bb0a4bd9f3", "lessThan": "4602b8cee1481dbb896182e5cb1e8cf12910e9e7", "status": "affected", "versionType": "git" }, { "version": "6bd7e0e55dcea2cf0d391bbc21c2eb069b4be3e1", "lessThan": "3412fbd81b46b9cfae013817b61d4bbd27e09e36", "status": "affected", "versionType": "git" }, { "version": "305853cce379407090a73b38c5de5ba748893aee", "lessThan": "88f170814fea74911ceab798a43cbd7c5599bed4", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/mgmt/user_session.c", "fs/smb/server/smb2pdu.c", "fs/smb/server/transport_ipc.c" ], "versions": [ { "version": "6.12.53", "lessThan": "6.12.55", "status": "affected", "versionType": "semver" }, { "version": "6.17.3", "lessThan": "6.17.5", "status": "affected", "versionType": "semver" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.53", "versionEndExcluding": "6.12.55" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.17.3", "versionEndExcluding": "6.17.5" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/5493571f4351f74e11db9943e98a07c56467cf7e" }, { "url": "https://git.kernel.org/stable/c/1891abe832cbf5a11039e088766131d0f1642d02" }, { "url": "https://git.kernel.org/stable/c/4602b8cee1481dbb896182e5cb1e8cf12910e9e7" }, { "url": "https://git.kernel.org/stable/c/3412fbd81b46b9cfae013817b61d4bbd27e09e36" }, { "url": "https://git.kernel.org/stable/c/88f170814fea74911ceab798a43cbd7c5599bed4" } ], "title": "ksmbd: fix recursive locking in RPC handle list access", "x_generator": { "engine": "bippy-1.2.0" } } } }