# CVE-2026-80831: crypto: mxs-dcp - fix source scatterlist length access

> A flaw in the Linux kernel's MXS DCP crypto driver causes incorrect data processing due to invalid DMA length access, potentially leading to data corruption or leakage.

- **Severity:** Not scored
- **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:** 4 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-99402, BELL-CVE-2026-80831, DEBIAN-CVE-2026-80831, GHSA-fv42-pvcm-2c76, UBUNTU-CVE-2026-80831

## What is CVE-2026-80831?

CVE-2026-80831 is a vulnerability in Linux, published on 4 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:

crypto: mxs-dcp - fix source scatterlist length access

mxs_dcp_aes_block_crypt() uses sg_dma_len() without mapping the source
scatterlist with dma_map_sg() first. Therefore, sg_dma_len() is invalid
and could return zero or a stale DMA length, causing encryption and
decryption to process the wrong number of bytes when
CONFIG_NEED_SG_DMA_LENGTH=y.

Use the original scatterlist length instead.

## Which versions are affected by CVE-2026-80831?


## How do I fix CVE-2026-80831?

Apply the vendor's patch.

## Is CVE-2026-80831 being exploited?

There is no known exploitation of CVE-2026-80831 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80831 and fix it if it is affected.

What it is: CVE-2026-80831 is a vulnerability in Linux, published on 4 Sep 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-2026-80831 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-2026-80831/ (Markdown: https://insights.sbomify.com/CVE-2026-80831/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80831
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80831
- OSV: https://osv.dev/vulnerability/CVE-2026-80831

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80831/
Summaries are generated and may contain mistakes; the official description above is the record.