CVE-2026-5818 PUBLISHED

MCU Firmware Update Authentication Bypass on Caliptra Core

Assigner: Caliptra
Reserved: 08.04.2026 Published: 23.06.2026 Updated: 24.06.2026

Incorrect check of function return value in Caliptra Core Runtime Firmware (ActivateFirmwareCmd::activate_fw modules) allows bypass of Caliptra Core's verification of the MCU FW during a hitless update.

This issue affects Core Runtime Firmware: from 2.0.0 through 2.0.1, 2.1.0.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:A/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:H/SC:H/SI:H/SA:H
CVSS Score: 7.2

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Adjacent	Confidentiality	None	Confidentiality	High
Attack Complexity	Low	Integrity	High	Integrity	High
Attack Requirements	Present	Availability	High	Availability	High
Privileges Required	High
User Interaction	None

CVSS 4.0

Product Status

Vendor	Caliptra
Product	Core Runtime Firmware
Versions	Default: unaffected affected from 2.0.0 to 2.0.1 (incl.) Version 2.1.0 is affected Version 2.0.2 is unaffected Version 2.1.1 is unaffected

Credits

NVIDIA Offensive Security Research (OSR) team finder

References

https://github.com/chipsalliance/caliptra-sw/security/advisories/GHSA-456r-gcjr-6rxq

Problem Types

CWE-253 Incorrect check of function return value CWE

Impacts

CAPEC-115 Authentication Bypass