CVE-2026-6458: AES-256-GCM Authentication Tag Does Not Cover First Ciphertext Blocks When AAD Is Empty
Caliptra · Core Runtime Firmware
Vendor fix available · Affected: Caliptra Core Runtime Firmware · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 9% of scored CVEs
DescriptionCVE.org
Missing cryptographic step in Caliptra Core Firmware (aes_256_gcm_update module) results in an incorrect GCM authentication tag. When the streaming AES-256-GCM API is used with empty AAD, the hardware GHASH accumulator state is not saved after the first update call, causing the final tag to exclude the first batch of processed ciphertext. Ciphertext produced by that call may be modified without the tag reflecting the change. This issue affects Core Runtime Firmware: from 2.0.0 through 2.0.1, 2.1.0.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- Caliptra · Core Runtime Firmwarefrom 2.0.0 up to and including 2.0.1; 2.1.0
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CoverageNo articles yet
No CyberSIXT article names CVE-2026-6458 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.