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

mediumCVSS 6.5CVE-2026-6330

CSIRTS triage

vendor: null product: nullOther

What: The ML-KEM ARM64 NEON ciphertext comparison only checks half of the input.
Who is affected: Deployments using affected versions of ML-KEM.
Urgency: Remediation is medium urgency due to the medium severity of the issue.
Action: Update to a patched version for CVE-2026-6330.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 6.5
Published: 2026-06-09
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-6330

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-63300.13% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 3% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-6330	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

mediumCVE-2026-6330: The ML-KEM ARM64 NEON ciphertext comparison only compares half of the input, breaking the Fujis…nvd

Recent advisories for ML-KEM ARM64 NEON

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

mediumCVE-2026-6330: The ML-KEM ARM64 NEON ciphertext comparison only compares half of the input, breaking the Fujis…nvd · 2026-06-25