CVE-2023-3866 ksmbd: validate session id and tree id in the compound request
A missing validation in the Linux kernel ksmbd module allows a remote attacker to cause a denial of service via a null pointer dereference.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-3866?
CVE-2023-3866 is a high-severity vulnerability in Linux kernel, published on 16 Aug 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:
ksmbd: validate session id and tree id in the compound request
This patch validate session id and tree id in compound request. If first operation in the compound is SMB2 ECHO request, ksmbd bypass session and tree validation. So work->sess and work->tcon could be NULL. If secound request in the compound access work->sess or tcon, It cause NULL pointer dereferecing error.
Weakness: CWE-476
Which versions are affected by CVE-2023-3866?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-3866?
Apply the vendor's patch.
Is CVE-2023-3866 being exploited?
There is no known exploitation of CVE-2023-3866 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-3866, DEBIAN-CVE-2023-3866, GHSA-hwfv-6r5j-7xm3, UBUNTU-CVE-2023-3866.