cve.bz

CVE-2025-40039

4.7 mediumEPSS 0.3%

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.

CVSS 3.1
4.7CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS
0.3% chance of exploitation in the next 30 days; higher than 23% of CVEs (scores of 2026-10-25)
CWE
CWE-362
Published
Modified
Record from
the NVD, synced

Affected

References

Check your stackJSON