# CVE-2026-43336: lib/crypto: chacha: Zeroize permuted_state before it leaves scope

> An attacker with memory access could recover cryptographic keys from the Linux kernel ChaCha implementation due to missing zeroization of stack variables.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 May 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-43336, DEBIAN-CVE-2026-43336, GHSA-cw2x-g67m-8387, ROOT-OS-DEBIAN-11-CVE-2026-43336, ROOT-OS-UBUNTU-2204-CVE-2026-43336, ROOT-OS-UBUNTU-2404-CVE-2026-43336, UBUNTU-CVE-2026-43336

## What is CVE-2026-43336?

CVE-2026-43336 is a high-severity vulnerability in Linux kernel, published on 8 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

lib/crypto: chacha: Zeroize permuted_state before it leaves scope

Since the ChaCha permutation is invertible, the local variable
'permuted_state' is sufficient to compute the original 'state', and thus
the key, even after the permutation has been done.

While the kernel is quite inconsistent about zeroizing secrets on the
stack (and some prominent userspace crypto libraries don't bother at all
since it's not guaranteed to work anyway), the kernel does try to do it
as a best practice, especially in cases involving the RNG.

Thus, explicitly zeroize 'permuted_state' before it goes out of scope.

## Which versions are affected by CVE-2026-43336?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43336?

Apply the vendor's patch.

## Is CVE-2026-43336 being exploited?

There is no known exploitation of CVE-2026-43336 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43336 and fix it if it is affected.

What it is: CVE-2026-43336 is a high-severity vulnerability in Linux kernel, published on 8 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-43336 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-43336/ (Markdown: https://insights.sbomify.com/CVE-2026-43336/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43336
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43336
- OSV: https://osv.dev/vulnerability/CVE-2026-43336

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43336/
Summaries are generated and may contain mistakes; the official description above is the record.