# CVE-2026-6330: ML-KEM ARM64 NEON ciphertext comparison only compares half of the input

> A flaw in wolfSSL's ARM64 NEON implementation allows attackers to bypass IND-CCA2 security checks by manipulating ciphertexts undetected.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Jun 2026
- **Updated:** 26 Jun 2026
- **Also known as:** DEBIAN-CVE-2026-6330, GHSA-89v8-3927-wfcg, JLSEC-2026-748, UBUNTU-CVE-2026-6330

## What is CVE-2026-6330?

CVE-2026-6330 is a medium-severity vulnerability in Wolfssl Wolfssl, published on 25 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The ML-KEM ARM64 NEON ciphertext comparison only compares half of the input, breaking the Fujisaki-Okamoto transform's implicit rejection and weakening IND-CCA2 security on that code path. The constant-time comparison effectively ignored part of the re-encrypted ciphertext, so a decapsulating party could fail to detect a manipulated ciphertext and proceed without the standard's required implicit rejection.

Weakness: CWE-327 (Use of a Broken or Risky Cryptographic Algorithm)

## Which versions are affected by CVE-2026-6330?

It affects 1 product.


Products: Wolfssl Wolfssl.

## How do I fix CVE-2026-6330?

Apply the vendor's patch.

## Is CVE-2026-6330 being exploited?

There is no known exploitation of CVE-2026-6330 in the wild and no public exploit code.

Public exploit code:

- Full ML-KEM-1024 key recovery from a partial Fujisaki-Okamoto comparison in wolfSSL (CVE-2026-6330 NEON, CVE-2026-10097 AVX2) (github_poc): https://github.com/007bsd/ml-kem-key-recovery

## Other vulnerabilities in Wolfssl Wolfssl

- [CVE-2024-5991](https://insights.sbomify.com/CVE-2024-5991/): Buffer overread in domain name matching (critical 10.0)
- [CVE-2021-37155](https://insights.sbomify.com/CVE-2021-37155/): Security feature bypass in n/a (critical 9.8)
- [CVE-2020-36177](https://insights.sbomify.com/CVE-2020-36177/): Memory corruption in n/a (critical 9.8)
- [CVE-2014-2896](https://insights.sbomify.com/CVE-2014-2896/): Memory corruption in n/a (critical 9.8)
- [CVE-2014-2897](https://insights.sbomify.com/CVE-2014-2897/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6330 and fix it if it is affected.

What it is: CVE-2026-6330 is a medium-severity vulnerability in Wolfssl Wolfssl, published on 25 Jun 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-2026-6330 in the wild and no public exploit code.

Affected product: Wolfssl Wolfssl. 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-2026-6330/ (Markdown: https://insights.sbomify.com/CVE-2026-6330/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6330
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6330
- OSV: https://osv.dev/vulnerability/CVE-2026-6330

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-6330/
Summaries are generated and may contain mistakes; the official description above is the record.