# CVE-2026-80836: crypto: virtio - bound the akcipher result length

> A malicious virtio backend can trigger an out-of-bounds read in the Linux kernel crypto subsystem, leaking adjacent kernel heap memory to the caller.

- **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-99546, BELL-CVE-2026-80836, DEBIAN-CVE-2026-80836, GHSA-4c27-p37x-4j2h, UBUNTU-CVE-2026-80836

## What is CVE-2026-80836?

CVE-2026-80836 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: virtio - bound the akcipher result length

virtio_crypto_dataq_akcipher_callback() sets the result length from the
device-reported response length without bounding it to the destination
buffer, which was allocated for the original request length.
sg_copy_from_buffer() then reads that many bytes from the destination
buffer; a backend reporting a larger length over-reads adjacent kernel
heap into the caller's scatterlist (an out-of-bounds read).

Clamp the reported length to the originally requested destination length.
A conforming device reports no more than that, so valid results are
unaffected.

## Which versions are affected by CVE-2026-80836?


## How do I fix CVE-2026-80836?

Apply the vendor's patch.

## Is CVE-2026-80836 being exploited?

There is no known exploitation of CVE-2026-80836 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80836 and fix it if it is affected.

What it is: CVE-2026-80836 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-2026-80836 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-2026-80836/ (Markdown: https://insights.sbomify.com/CVE-2026-80836/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80836
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80836
- OSV: https://osv.dev/vulnerability/CVE-2026-80836

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80836/
Summaries are generated and may contain mistakes; the official description above is the record.