Ciphertext tampering via discarded GHASH state
Published Jun 23, 2026 · Updated Jun 24, 2026
Missing cryptographic step in Caliptra Runtime Firmware 2.0.0 through 2.0.1 and 2.1.0 allows attackers to alter ciphertext undetected. The aes_256_gcm_update function discards the hardware GHASH accumulator after the first streaming update when AAD is empty, so the final authentication tag omits that call's ciphertext. Exploitation requires low-privileged access to the adjacent cryptographic mailbox and use of the streaming API with empty AAD; resulting modifications can affect downstream data integrity.
Summary
What happened
Missing cryptographic step in Caliptra Runtime Firmware 2.0.0 through 2.0.1 and 2.1.0 allows attackers to alter ciphertext undetected. The aes_256_gcm_update function discards the hardware GHASH accumulator after the first streaming update when AAD is empty, so the final authentication tag omits that call's ciphertext. Exploitation requires low-privileged access to the adjacent cryptographic mailbox and use of the streaming API with empty AAD; resulting modifications can affect downstream data integrity.
The record
- CVE
- CVE-2026-6458
- Published
- Jun 23, 2026
- Updated
- Jun 24, 2026
- Vendor
- Caliptra
- Product
- Caliptra Runtime Firmware
- Classifications
- CWE-325, T1565
- Attack vector
- adjacent
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 23, 2026CVE publishedPublication date reported by the CVE source.
- Jun 24, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.0.0 <=2.0.1
- Affected versionversion=2.1.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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