Is CVE-2026-6330 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-6330 being exploited in the wild.

How severe is CVE-2026-6330?

Informational severity, with a CVSS score of 6.3, published 25 June 2026.

Is there a fix for CVE-2026-6330?

A patch was published on 2026-04-15: Fix merged into master branch via PR 10192 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-6330 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-6330?

Check whether you run Wolfssl at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-6330: wolfSSL ML-KEM partial ciphertext comparison on ARM64 NEON

CVE-2026-6330 · Severity: info · CVSS 6.3 · Published 2026-06-25

wolfSSL is a cryptographic library used to secure communications for embedded devices and cloud services. A flaw was discovered in its implementation of ML-KEM (a post-quantum encryption standard) where the system only checked half of the security data during decryption on ARM64 processors. This could allow a sophisticated attacker to bypass certain security checks, potentially compromising the confidentiality of encrypted data.

Technologies: Wolfssl. Vendors: Wolfssl.

Quick answers

Is CVE-2026-6330 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-6330 being exploited in the wild.
How severe is CVE-2026-6330?: Informational severity, with a CVSS score of 6.3, published 25 June 2026.
Which products and versions are affected?: Wolfssl 5.7.4 to 5.9.0.
Is there a fix for CVE-2026-6330?: A patch was published on 2026-04-15: Fix merged into master branch via PR 10192 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-6330 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-6330?: Check whether you run Wolfssl at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A vulnerability exists in the wolfSSL ML-KEM implementation specifically for ARM64 NEON optimized code paths. The constant-time ciphertext comparison logic (mlkem_cmp_neon) in the Fujisaki-Okamoto (FO) transform only compared the lower 64 bits of the input, effectively ignoring the upper half of the re-encrypted ciphertext. This failure to perform a full comparison breaks the implicit rejection mechanism required by the ML-KEM standard, weakening IND-CCA2 security. An attacker could potentially manipulate ciphertexts without detection by the decapsulating party. The issue was resolved by adjusting the NEON reduction step to fold the upper 64 bits into the lower before the scalar check.

Affected products

wolfSSL wolfSSL 5.7.4 to 5.9.0

Timeline

2026-04-15: patched: Fix merged into master branch via PR 10192
2026-06-25: disclosed: CVE published and advisory released

References

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