# CVE-2026-6458

## Summary

- **CVE ID:** CVE-2026-6458
- **Severity:** MEDIUM
- **CVSS Score:** 5.1 (CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N)
- **CWE:** CWE-325
- **Published:** Jun 23, 2026
- **Last Modified:** Jun 24, 2026

## 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

- Caliptra — Core Runtime Firmware (2.0.0)
- Caliptra — Core Runtime Firmware (2.1.0)
- Caliptra — Core Runtime Firmware (2.0.2)
- Caliptra — Core Runtime Firmware (2.1.1)

## References

- [CNA](https://github.com/chipsalliance/caliptra-sw/security/advisories/GHSA-834g-h5x6-2hqr)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.20%
- **EPSS Percentile:** 9.6

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._