CVE-2025-37954 smb: client: Avoid race in open_cached_dir with lease breaks
A race condition in the Linux kernel SMB client can leak dentry references, potentially leading to resource exhaustion and denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-37954?
CVE-2025-37954 is a high-severity vulnerability in Linux kernel, published on 20 May 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
smb: client: Avoid race in open_cached_dir with lease breaks
A pre-existing valid cfid returned from find_or_create_cached_dir might race with a lease break, meaning open_cached_dir doesn't consider it valid, and thinks it's newly-constructed. This leaks a dentry reference if the allocation occurs before the queued lease break work runs.
Avoid the race by extending holding the cfid_list_lock across find_or_create_cached_dir and when the result is checked.
Which versions are affected by CVE-2025-37954?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-37954?
Apply the vendor's patch.
Is CVE-2025-37954 being exploited?
There is no known exploitation of CVE-2025-37954 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-37954, DEBIAN-CVE-2025-37954, GHSA-hxv7-wmrf-q57m, ROOT-OS-DEBIAN-11-CVE-2025-37954, ROOT-OS-DEBIAN-12-CVE-2025-37954, ROOT-OS-UBUNTU-2204-CVE-2025-37954 and 2 more.