AES-256-GCM Authentication Tag Does Not Cover First Ciphertext Blocks When AAD Is Empty
Description
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
1- Range: >=2.0.0 <=2.0.1, 2.1.0
Patches
Vulnerability mechanics
No source-code context for this CVE — mechanics is only generated when we can read the actual fix diff. Without that, the four sections (root cause, attack vector, affected code, fix) would be speculation rather than analysis.
References
1News mentions
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