VulnerabilityAwaiting Analysis

CVE-2026-6458

Missing cryptographic step in Caliptra Core Firmware (aes_256_gcm_update module) results in an incorrect GCM authentication tag.

MEDIUM 5.1EPSS 0.20%

Does this matter?

Lower severity and a low EPSS score (0.20%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 4.0: 5.1 MEDIUMCVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.20% probability · 10th percentile
CISA KEV: Not listed
Weakness: CWE-325
Source: b01ddd03-5ef6-483b-b2c5-acba77f1a554

References

https://github.com/chipsalliance/caliptra-sw/security/advisories/GHSA-834g-h5x6-2hqr

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.