FKIE_CVE-2025-40039

Vulnerability from fkie_nvd - Published: 2025-10-28 12:15 - Updated: 2026-02-26 15:50
Severity ?
4.7 (Medium) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: Fix race condition in RPC handle list access The 'sess->rpc_handle_list' XArray manages RPC handles within a ksmbd session. Access to this list is intended to be protected by 'sess->rpc_lock' (an rw_semaphore). However, the locking implementation was flawed, leading to potential race conditions. In ksmbd_session_rpc_open(), the code incorrectly acquired only a read lock before calling xa_store() and xa_erase(). Since these operations modify the XArray structure, a write lock is required to ensure exclusive access and prevent data corruption from concurrent modifications. Furthermore, ksmbd_session_rpc_method() accessed the list using xa_load() without holding any lock at all. This could lead to reading inconsistent data or a potential use-after-free if an entry is concurrently removed and the pointer is dereferenced. Fix these issues by: 1. Using down_write() and up_write() in ksmbd_session_rpc_open() to ensure exclusive access during XArray modification, and ensuring the lock is correctly released on error paths. 2. Adding down_read() and up_read() in ksmbd_session_rpc_method() to safely protect the lookup.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/305853cce379407090a73b38c5de5ba748893aeePatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5cc679ba0f4505936124cd4179ba66bb0a4bd9f3Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/69674b029002b1d90b655f014bdf64f404efa54dPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6b615a8fb3af0baf8126cde3d4fee97d57222ffcPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6bd7e0e55dcea2cf0d391bbc21c2eb069b4be3e1Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
To clipboard 

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: Fix race condition in RPC handle list access\n\nThe \u0027sess-\u003erpc_handle_list\u0027 XArray manages RPC handles within a ksmbd\nsession. Access to this list is intended to be protected by\n\u0027sess-\u003erpc_lock\u0027 (an rw_semaphore). However, the locking implementation was\nflawed, leading to potential race conditions.\n\nIn ksmbd_session_rpc_open(), the code incorrectly acquired only a read lock\nbefore calling xa_store() and xa_erase(). Since these operations modify\nthe XArray structure, a write lock is required to ensure exclusive access\nand prevent data corruption from concurrent modifications.\n\nFurthermore, ksmbd_session_rpc_method() accessed the list using xa_load()\nwithout holding any lock at all. This could lead to reading inconsistent\ndata or a potential use-after-free if an entry is concurrently removed and\nthe pointer is dereferenced.\n\nFix these issues by:\n1. Using down_write() and up_write() in ksmbd_session_rpc_open()\n   to ensure exclusive access during XArray modification, and ensuring\n   the lock is correctly released on error paths.\n2. Adding down_read() and up_read() in ksmbd_session_rpc_method()\n   to safely protect the lookup."
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  "id": "CVE-2025-40039",
  "lastModified": "2026-02-26T15:50:57.663",
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          "attackVector": "LOCAL",
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          "baseScore": 4.7,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
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          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
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