CVE-2023-54076 smb: client: fix missed ses refcounting
A use-after-free vulnerability in the Linux kernel SMB client allows attackers to potentially execute code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-54076?
CVE-2023-54076 is a critical use after free vulnerability in Linux, published on 24 Dec 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: fix missed ses refcounting
Use new cifs_smb_ses_inc_refcount() helper to get an active reference of @ses and @ses->dfs_root_ses (if set). This will prevent @ses->dfs_root_ses of being put in the next call to cifs_put_smb_ses() and thus potentially causing an use-after-free bug.
Which versions are affected by CVE-2023-54076?
How do I fix CVE-2023-54076?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2023-54076 being exploited?
There is no known exploitation of CVE-2023-54076 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-54076, DEBIAN-CVE-2023-54076, GHSA-fm2q-hj9m-hx9r, UBUNTU-CVE-2023-54076.