CVE-2023-3865 ksmbd: fix out-of-bound read in smb2_write
An out-of-bounds read in the ksmbd SMB2 write handler allows attackers to cause denial of service or read sensitive memory.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-3865?
CVE-2023-3865 is a high-severity memory corruption vulnerability in Linux kernel, published on 16 Aug 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix out-of-bound read in smb2_write
ksmbd_smb2_check_message doesn't validate hdr->NextCommand. If ->NextCommand is bigger than Offset + Length of smb2 write, It will allow oversized smb2 write length. It will cause OOB read in smb2_write.
Weakness: CWE-125
Which versions are affected by CVE-2023-3865?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-3865?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2023-3865 being exploited?
There is no known exploitation of CVE-2023-3865 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-3865, DEBIAN-CVE-2023-3865, GHSA-mr68-gqxj-cfm9, UBUNTU-CVE-2023-3865.