CVE-2025-40055 ocfs2: fix double free in user_cluster_connect()
A double free vulnerability in the Linux kernel OCFS2 module allows local attackers to cause a denial of service or potentially escalate privileges.
- 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-2025-40055?
CVE-2025-40055 is an use after free vulnerability in Linux, published on 28 Oct 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:
ocfs2: fix double free in user_cluster_connect()
user_cluster_disconnect() frees "conn->cc_private" which is "lc" but then the error handling frees "lc" a second time. Set "lc" to NULL on this path to avoid a double free.
Which versions are affected by CVE-2025-40055?
How do I fix CVE-2025-40055?
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-2025-40055 being exploited?
There is no known exploitation of CVE-2025-40055 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-40055, DEBIAN-CVE-2025-40055, GHSA-xrxh-pcqg-5r4x, ROOT-OS-DEBIAN-11-CVE-2025-40055, ROOT-OS-DEBIAN-12-CVE-2025-40055, ROOT-OS-DEBIAN-13-CVE-2025-40055 and 3 more.