CVE-2026-68340 hwmon: occ: validate poll response sensor blocks
A missing bounds check in the Linux kernel OCC driver allows a truncated response to cause out-of-bounds reads, potentially leading to a system crash.
- 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-2026-68340?
CVE-2026-68340 is a high-severity denial of service vulnerability in Linux, published on 10 Aug 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:
hwmon: occ: validate poll response sensor blocks
The OCC poll response parser walks a counted list of sensor data blocks. It used the static backing-array capacity as the parse boundary, but a transport response makes only data_length bytes current and valid. A truncated response can therefore make the parser consume a block header or block extent outside the current response.
Use data_length as the parent boundary, prove the fixed poll header and each current block header before reading them, and prove the complete block before advancing. Keep parsed sensor metadata local until the complete response has passed validation, then publish it. Propagate malformed-response errors before publishing the OCC as active.
Which versions are affected by CVE-2026-68340?
How do I fix CVE-2026-68340?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-68340 being exploited?
There is no known exploitation of CVE-2026-68340 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68340, DEBIAN-CVE-2026-68340, GHSA-jq56-qr42-62xw, UBUNTU-CVE-2026-68340.