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CVE PROGRAM SOURCE RECORD5.1 Medium

CVE-2026-6458

AES-256-GCM Authentication Tag Does Not Cover First Ciphertext Blocks When AAD Is Empty

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Status
Published
Published
Updated
Assigning organization
Caliptra

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Caliptra Core Runtime Firmware

Default version status: unaffected

  • 2.0.0 to ≤ 2.0.1affected
  • 2.1.0affected
  • 2.0.2unaffected
  • 2.1.1unaffected

References