CVE-2026-6330Network attack vector

Cryptographic integrity bypass via half-length ciphertext comparison

Published Jun 25, 2026 · Updated Jun 25, 2026

Cryptographic verification bypass in wolfSSL 5.7.4 through 5.9.1 allows remote attackers to weaken ML-KEM ciphertext integrity. The ARM64 mlkem_cmp_neon reduction omits the upper half of the comparison result, allowing altered re-encrypted ciphertext to compare as equal. Exposure requires an ARM64 build with NEON assembly and ML-KEM enabled; manipulated ciphertext can evade Fujisaki-Okamoto rejection, weakening confidentiality and integrity.

CVSS severity6.3
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cryptographic verification bypass in wolfSSL 5.7.4 through 5.9.1 allows remote attackers to weaken ML-KEM ciphertext integrity. The ARM64 mlkem_cmp_neon reduction omits the upper half of the comparison result, allowing altered re-encrypted ciphertext to compare as equal. Exposure requires an ARM64 build with NEON assembly and ML-KEM enabled; manipulated ciphertext can evade Fujisaki-Okamoto rejection, weakening confidentiality and integrity.

The record

CVE
CVE-2026-6330
Published
Jun 25, 2026
Updated
Jun 25, 2026
Vendor
wolfSSL
Product
wolfSSL
Classifications
CWE-327
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.7.4 <=5.9.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

wolfSSL · wolfSSLversion=5.7.4 <=5.9.1

Published CVSS scores

6.3wolfSSL Inc.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
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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