# 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.

- **Severity:** High 7.7 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** BELL-CVE-2026-68340, DEBIAN-CVE-2026-68340, GHSA-jq56-qr42-62xw, UBUNTU-CVE-2026-68340

## 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.

## Is CVE-2026-68340 being exploited?

There is no known exploitation of CVE-2026-68340 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68340 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-68340 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-68340/ (Markdown: https://insights.sbomify.com/CVE-2026-68340/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68340
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68340
- OSV: https://osv.dev/vulnerability/CVE-2026-68340

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68340/
Summaries are generated and may contain mistakes; the official description above is the record.