CVE-2026-6330

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.

CVSS v4.0

6.3 MEDIUMCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1

6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS

0.17% chance of exploitation in the next 30 days, 6th percentile

Published

2026-06-25

Updated

2026-06-26

Proof-of-concept exploits (1)

• 007bsd/ml-kem-key-recovery0★ · 2026-08-15

References

• CVE Record
• NVD entry

Related

• CVE-2026-10097
• CVE-2026-63223
• CVE-2026-63308
• CVE-2026-63188
• CVE-2026-63335
• CVE-2026-63135