CVE-2025-39825 smb: client: fix race with concurrent opens in rename(2)
A race condition in the Linux kernel SMB client during rename operations allows concurrent opens, potentially leading to inconsistent file states.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-39825?
CVE-2025-39825 is a high-severity vulnerability in Debian Debian Linux, published on 16 Sep 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-362
Which versions are affected by CVE-2025-39825?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-39825?
Apply the vendor's patch.
Is CVE-2025-39825 being exploited?
There is no known exploitation of CVE-2025-39825 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-67386, BELL-CVE-2025-39825, DEBIAN-CVE-2025-39825, GHSA-3f3q-q5cj-phc5, ROOT-OS-DEBIAN-11-CVE-2025-39825, ROOT-OS-DEBIAN-12-CVE-2025-39825 and 4 more.