CVE-2026-97565 smb: client: reject short READ responses in CIFSSMBRead()
A malicious SMB1 server can trigger a buffer over-read in the Linux kernel SMB client, potentially causing a crash or code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-97565?
CVE-2026-97565 is a memory corruption vulnerability in Linux, published on 25 Sep 2026. 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:
smb: client: reject short READ responses in CIFSSMBRead()
CIFSSMBRead() reads DataLengthHigh, DataLength and DataOffset out of the READ_RSP returned by the server without first checking that a whole READ_RSP was actually received. The length of the response is recorded in rsp_iov.iov_len, but nothing constrains it to be at least read_rsp_size before those fields are dereferenced.
A malicious or compromised SMB1 server can return a response shorter than the READ_RSP header, so that parsing the header itself reads past the end of the receive buffer. SMB1 is not negotiated by default; reaching this code requires an explicit vers=1.0 mount.
Reject the response unless it is at least read_rsp_size bytes long.
Which versions are affected by CVE-2026-97565?
How do I fix CVE-2026-97565?
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-2026-97565 being exploited?
There is no known exploitation of CVE-2026-97565 in the wild and no public exploit code.
Sources
Also known as AZL-104462, BELL-CVE-2026-97565, DEBIAN-CVE-2026-97565, GHSA-c543-5m5v-x4wf, UBUNTU-CVE-2026-97565.