CVE-2025-39825

In the Linux kernel, the following vulnerability has been resolved:

smb: client: fix race with concurrent opens in rename(2)

Besides sending the rename request to the server, the rename process also involves closing any deferred close, waiting for outstanding I/O to complete as well as marking all existing open handles as deleted to prevent them from deferring closes, which increases the race window for potential concurrent opens on the target file.

Fix this by unhashing the dentry in advance to prevent any concurrent opens on the target.

This vulnerability is rated as Moderate severity for Red Hat Enterprise Linux because exploitation requires local access and precise timing to trigger a race condition during concurrent file operations on an active SMB mount. While a race condition can cause file handle inconsistencies or kernel instability, it cannot be exploited remotely over the network. Furthermore, SMB network filesystems are not mounted by default in standard Red Hat deployments, restricting exposure to environments explicitly utilizing CIFS shares.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.